Guides & Articles
Plain-English guides to the money questions behind our 58+ calculators.
How much to save per month to reach your goal: formula, examples, and shortcut
Learn exactly how much to save per month to reach your goal. Free formula, real examples for $10K-$60K goals, and a 30-second mental shortcut you can use today.
How to build a 6-month emergency fund: the complete step-by-step plan
Learn how to build a 6 month emergency fund step by step: exact math, HYSA picks, milestones, and timelines to reach a fully funded $20K+ cushion.
How to calculate a pay raise: percentage, hourly, and annual examples
Learn how to calculate a pay raise in percentage, hourly, and annual terms with US formulas, worked examples, inflation math, and a free pay raise calculator.
Salary to hourly conversion: the formula, the math, and how to compare jobs fairly
Salary to hourly conversion explained: the 2,080-hours formula, worked examples, effective hourly rate, and how to compare salaried vs hourly jobs fairly.
How to calculate CAGR: formula, Excel method, and worked examples
Learn how to calculate CAGR with the formula, Excel, and real worked examples. Avoid common mistakes and find your true compound annual growth rate fast.
How to calculate unit price: the simple way to find the best deal
Learn how to calculate unit price with the simple formula (price / quantity), real examples, and tips to spot the better buy and save on every shopping trip.
How to calculate CD interest: APY, the formula, and what banks rarely tell you
Learn how to calculate CD interest using APY and the compound interest formula, with worked dollar examples, penalty math, and a free CD calculator.
How to Build a CD Ladder: Strategy, Steps, and a $25,000 Example
Learn how to build a CD ladder step by step, with a worked 5-year $25,000 example, mini-ladders, barbell vs bullet, and when not to ladder for liquidity.
How Is a CD Early Withdrawal Penalty Calculated? Formula, Tiers, and Worked Examples
See how a CD early withdrawal penalty is calculated, with the formula, penalty tiers by term, a worked $10,000 example, and the break-even math.
How to Calculate Hourly Rate From Salary: The Step-by-Step Formula
Calculate hourly rate from salary with the 2,080-hour formula, a worked $60,000 example, and a salary-to-hourly chart so you know your true wage fast.
Salary to Hourly Conversion Chart: $30k–$150k Reference Table
Salary to hourly conversion chart for $30k–$150k: see hourly, weekly, biweekly, and monthly pay at 2,080 hours, plus real rates at 45 and 50 hours a week.
How to Use Reverse CAGR to Project Future Value
Use reverse CAGR to project future value: EV = BV x (1 + CAGR)^n. Worked example, Excel formula, and a multi-rate growth table to forecast any investment.
CAGR vs Average Annual Return: What's the Difference?
CAGR vs average annual return explained with a worked +40%/-20% example, a side-by-side table, and when to trust each number for honest returns.
How to Calculate a Pay Raise Percentage
Learn how to calculate a pay raise percentage both ways: apply a percent to find your new salary, or work backward from old and new pay to find the percent.
Is a 3 Percent Raise Good? Real Raise vs. Inflation
Is a 3 percent raise good? See the real-raise formula, a nominal-vs-inflation table for 2%-6% raises, average raise benchmarks, and how to negotiate more.
How Much Emergency Fund Do I Need? Sizing It for Your Situation
How much emergency fund do you need? Use the months-of-coverage formula plus a situation table to size 3, 6, or 9-12 months of essential expenses in 2026.
Where Should I Keep My Emergency Fund? Best Accounts Compared
Where should you keep your emergency fund? Compare high-yield savings, money market, no-penalty CD, and T-bills on liquidity, yield, and insurance for 2026.
How Long Will It Take to Reach My Savings Goal?
Find out how long it takes to reach your savings goal at any monthly amount. Use the time formula, a worked $30,000 example, and a months-to-goal table.
What Is a Sinking Fund and How to Use One (With Categories + Examples)
A sinking fund is money you save monthly for a known future expense. Learn sinking fund categories, real example amounts, and how to budget for irregular bills.
How to Calculate Price Per Unit: Formula, Conversions, and Worked Examples
Learn how to calculate price per unit with the simple formula, oz/lb/gram/count examples, multipack and coupon math, and a table for finding the cheapest buy.
How to Find the Better Buy Using Unit Price
Learn how to find the better buy using unit price. Convert both sizes to cost per ounce, compare, and stop overpaying — with real examples and a mental-math trick.
How to Convert a Nominal Rate to APY: The Effective Yield Formula
Convert any nominal interest rate to APY in seconds. The exact formula, a worked rate table, the compounding-frequency effect, and continuous compounding.
How to Back-Solve the Nominal Rate From an APY
Back-solve the nominal rate from any advertised APY. The reverse formula, a worked example, the APY-to-APR step for loans, and a quick reference table.
How Much to Save for College by Age, With a Tuition-Inflation Math Breakdown
How much to save for college by your child's age, with a 529 save-by-age table, tuition-inflation math, and how much of the bill your plan really covers.
529 Plan Tax Benefits Explained: Tax-Free Growth, State Deductions, and a Worked Example
How 529 tax benefits work: tax-free qualified growth, state deductions, and a worked example showing roughly $13,700 more than a taxable account over 18 years.
Future Value of a Lump Sum, Explained
Learn the future value of a lump sum: the FV = PV(1+r)^n formula, by-hand and Excel =FV() methods, nominal vs real, plus a $10,000-$100,000 growth table.
Using Future Value to Compare Lump-Sum Offers
Cash now vs more later? Learn to compare lump-sum offers, signing bonuses, and annuity payouts on a level field using future value, with worked examples.
How Much Will Things Cost in the Future? An Inflation Guide
See how much things will cost in the future. Inflation math, real US averages, a forward-cost table, and how to price goals, bills, and retirement in tomorrow's dollars.
What Will My Money Be Worth in the Future?
Find out what your money will be worth in the future. See how inflation shrinks purchasing power, why idle cash loses value, and how real returns reveal true growth.
What Rate of Return Should You Use in an Investment Calculator?
Use about 10% for a nominal stock projection or 7% after inflation, then subtract your fees. Here is how to pick an honest return rate, with worked examples.
Why Your Investment Projection Is Wrong - and How to Make It Honest
An investment projection shows one smooth midpoint, but real returns are bumpy. Learn volatility drag, sequence risk, and how to project an honest range.
How Long Does It Take to Become a Millionaire?
How long to reach $1,000,000? See the years-to-a-million table by monthly contribution and return, the levers that move it most, and what $1M will really buy.
What Discount Rate Should You Use in a Present Value Calculation?
Your discount rate is your opportunity cost — the return you give up by waiting. Here is how to pick a reasonable one and why a higher rate slashes present value.
How to Find the Present Value of a Single Future Lump Sum
Discount one future amount to today's value with PV = FV / (1 + r)^n. Worked examples, a sensitivity table, and the exact Excel =PV() formula to copy.
How Long Until Prices Double? Use 72 Divided by Inflation
Divide 72 by the inflation rate to estimate when prices double. At 3% inflation, prices double in about 24 years. See the math, a table, and what it means for you.
How Accurate Is the Rule of 72?
The Rule of 72 is most accurate from 5% to 12%, where it is within ~1% of the exact ln(2)/ln(1+r) answer. See the drift at extremes and how to fix it.
How Much Will My Savings Grow With Monthly Deposits?
See how a starting balance plus monthly deposits grows in a savings account at a given APY, with worked examples, a growth table, and the variable-rate catch.
High-Yield Savings vs Regular Savings: How Much More You Earn
A high-yield savings account can pay roughly 10x a typical big-bank rate. See the dollar difference, FDIC protection, and the taxes you owe on the interest.
How to Calculate Simple Interest: Formula, By Hand, and in Excel
Learn how to calculate simple interest with the I = P x R x T formula, worked dollar examples, day-count rules, and a copy-paste Excel formula.
Simple Interest vs Compound Interest: How the Dollar Gap Grows Over Time
See the exact dollar gap between simple and compound interest over 1 to 30 years, why it explodes with time, and which one applies to your loan or savings.
How a SIP Calculator Works: The Formula, a Worked Example, and What the Numbers Really Mean
See exactly how a SIP calculator works, with the annuity-due formula, a worked $500/month example, and why your invested amount and gains are different things.
Step-Up SIP: How Raising Your Investment Each Year Changes the Math
A step-up SIP raises your monthly investment a fixed % each year. See how a 10% annual increase nearly doubles a flat SIP, with worked numbers and a yearly table.
401(k) Employer Match Explained: The Free Money Most Workers Leave on the Table
How 401(k) employer match formulas work, what leaving it costs over 30 years, plus vesting schedules and the 2026 IRS contribution limits, with worked math.
What to Do With an Old 401(k): Your Four Options and the Real Cost of Each
Your four options for an old 401(k) after leaving a job, the true cost of cashing out, Roth vs traditional rollover math, and the 2026 IRS limits.
What Is My FIRE Number, and How Do You Calculate It?
Your FIRE number is annual spending times 25 at a 4% withdrawal rate. See how to calculate it, gross it up for taxes and healthcare, and the right multiple to use.
Coast FIRE: How Much You Need So You Can Stop Saving
Coast FIRE is the amount invested today that grows into your full retirement nest egg with no new contributions. See the number by age and how to calculate it.
How Much Money Do I Need to Retire?
How much you need to retire equals about 25 times your annual spending, minus Social Security and pensions. See the 25x and income-replacement math with tables.
Is Saving 15% of Your Income Enough to Retire?
Saving 15% of income from your 20s is usually enough to retire; start later and you need more. See the 15% math, percent-by-age tables, and catch-up options.
How Much Monthly Income Does $1 Million Produce in Retirement?
A $1 million nest egg produces about $40,000 a year, or $3,333 a month, at the 4% rule. See the income table by portfolio size and withdrawal rate.
How Big a Nest Egg Do You Need for the Retirement Income You Want?
To retire on $40,000 a year you need about $1 million at the 4% rule. See the nest egg required for any target income and the 25x shortcut.
Roth IRA Tax-Free Growth vs a Taxable Account: What the Tax Break Is Really Worth
A Roth IRA grows and pays out tax-free. See how that beats a taxable account by about $104,000 on $7,500/yr for 30 years, with worked numbers.
How Much Will My Roth IRA Be Worth at Retirement?
Maxing a Roth IRA at $7,500/yr to age 65 at 7% grows to about $709k starting at 35 or $1.04M starting at 30, all tax-free. See the numbers by age.
Upside Down on Your Car Loan? Negative Equity Explained
Negative equity means you owe more than your car is worth. See why depreciation and long loans cause it, what gap insurance covers, and how to climb out.
Out the Door Price vs Sticker: What You Actually Finance
The out the door price, not the sticker, sets your car loan. See how tax and fees inflate the amount financed, plus the new vs used and dealer vs bank rate gap.
How Biweekly Mortgage Payments Add One Extra Payment a Year
See exactly how 26 half-payments equal 13 monthly payments, why that one extra payment saves ~5-6 years and tens of thousands in interest, plus a DIY shortcut.
DIY Biweekly Mortgage Payments vs Paid Third-Party Programs
Paid biweekly mortgage programs charge setup and per-transaction fees for something you can do free. Here is how to set it up yourself and keep the savings.
How Much of a Down Payment Do You Need to Avoid PMI?
You need 20% down to skip PMI on a conventional loan. See the exact cash, how PMI works, when it cancels, and what less-than-20% really costs.
How Long Does It Take to Save for a Down Payment?
Saving $40,000 at $1,000/month takes about 38 months in a 4% high-yield account. See the timeline math, where to keep the cash, and how to save faster.
How Much Does Paying Extra on Your Mortgage Save?
See how any extra principal payment shortens your loan and slashes interest. Real numbers for recurring extra vs a one-time lump sum, plus the simple math.
Should You Pay Extra on Your Mortgage, or Use That Money Elsewhere?
Before prepaying a cheap mortgage, send extra cash where it earns the most. The order to follow, recast vs refinance, and how to spot prepayment penalties.
Home Equity Loan vs HELOC vs Cash-Out Refinance: Which Is Right for You?
Three ways to tap home equity, compared side by side: fixed home equity loan, revolving HELOC, and cash-out refinance. See payments, rates, and when each wins.
Should You Use a Home Equity Loan to Pay Off Credit Card Debt?
A home equity loan can slash credit card interest - but it swaps unsecured debt for debt secured by your home. See the real math, the risks, and when it's worth it.
How Recasting an Interest-Only Mortgage Lowers Your Future Payment
Recasting an interest-only mortgage re-amortizes a lower balance, softening the payment jump when full P&I begins. See the math, steps, and a worked example.
Interest-Only Mortgages Build Zero Equity - and Why That Is a Bet on Appreciation
An interest-only mortgage builds no equity during the IO period, so your home must appreciate to come out ahead. See the math on what happens at sale.
How Much Can I Borrow From a Monthly Payment? Work Backward
Start with the payment you can afford and work backward to the maximum loan. See how rate and term change your borrowing power, with a recomputed table.
How Much Should I Borrow vs. How Much Can I Borrow?
The maximum loan you can afford is rarely the amount you should take. See how the 28/36 DTI rule sets a safer ceiling and why approval is never guaranteed.
Does a Debt Consolidation Loan Actually Save You Money?
A consolidation loan saves money only when its APR (after fees) is well below your current rate. Here's the math, with worked examples and a break-even check.
How to Calculate Any Loan Payment (by Hand, Excel, or Calculator)
One formula sets the monthly payment for any fixed-rate loan. See the amortization formula, an Excel one-liner, a worked example, and credit-tier rate benchmarks.
Mortgage Refinance Break-Even Point: How Long Until a Refi Pays Off
Find your refinance break-even point: divide closing costs by monthly savings to get the months to recoup. See the formula, a worked example, and benchmarks.
Why a Lower Rate Can Cost More: The Fresh-30-Year Refinance Trap
A lower refinance rate can still raise your lifetime interest if you reset to a new 30-year term. See the math, a side-by-side table, and how to avoid the trap.
How a Balloon Loan Keeps Your Payments Low (and What the Balloon Really Costs)
A balloon loan keeps payments low by amortizing over a long schedule, then ending in one big lump sum. See exactly how it works and what you still owe.
Balloon Loan Refinancing Risk: What If You Can't Refinance?
The biggest danger of a balloon loan is being unable to refinance the lump sum when it's due. Here's what raises the risk and how to protect yourself.
Why Boat Loans Have Such Long Terms - and What It Really Costs
Boat loans run 10-20 years to keep payments low, but a long term piles on interest while the boat depreciates. See the real numbers before you sign.
The True Cost of Owning a Boat - Beyond the Monthly Payment
Your boat loan payment is only part of the cost. Add insurance, storage, winterizing and upkeep - then see how the second-home tax deduction helps.
The Personal Guarantee on a Business Loan: What You Are Really Signing
What a personal guarantee on a business loan means, how blanket UCC-1 liens and joint-and-several clauses work, when you can avoid one, and how to build business credit.
How to Compare Business Loan Offers: APR, Factor Rates, and True Cost
Convert factor rates to APR, fold in origination and packaging fees, and compare business loan offers apples-to-apples by total dollar cost. Worked $50,000 examples.
Are Mortgage Discount Points Worth It? Run the Break-Even Math First
Mortgage points lower your rate for an upfront fee. Here is the simple break-even formula and a worked example showing exactly when buying points pays off.
Conforming vs Jumbo Mortgage: The Loan Limit, the Rate, and the Down Payment
A jumbo loan exceeds the annual conforming loan limit and usually has stricter rules. Here is how the two compare on rates, down payment, and qualifying.
Is RV Loan Interest Tax Deductible? The Second-Home Rule Explained
Yes, RV loan interest can be deductible if your camper qualifies as a second home with sleeping, cooking and toilet facilities. See the rules and the math.
How Long Should an RV Loan Be? Choosing a Term by RV Type
RV loans run 10-20 years, far longer than a car loan. See how Class A, B, C and towable trailers change the right term, and how to avoid going underwater.
Federal vs Private Student Loans: Repayment Plans, IDR, and Forgiveness
Federal vs private student loans, the standard 10-year plan vs income-driven repayment (IDR), and how PSLF forgiveness works - explained with real numbers.
Student Loan Interest: Grace Period, Capitalization, and the Refinance Trade-Off
How subsidized vs unsubsidized interest, the grace period, and capitalization quietly raise your balance - plus when refinancing a student loan actually pays off.
Why Minimum Payments Take Decades to Pay Off (and How to Escape)
Paying only the minimum can take 16+ years and cost more interest than you borrowed. See the trap math, a real payoff schedule, and the one fix that breaks it.
What the Credit Card Minimum Payment Warning Box Means
Every US card statement has a minimum payment warning box required by the CARD Act. Here's what its two payoff numbers mean and how to actually use them.
How a Fixed Monthly Payment Clears a Credit Card Years Faster
Locking in one fixed monthly payment beats a shrinking minimum by years. See the math, the daily periodic rate behind it, and a worked $5,000 example.
Balance Transfers and Deferred Interest: The Fee, the 0% Cliff, and the Retroactive Trap
A 0% balance transfer only pays off if you clear it before the cliff. See the 3-5% fee math, the promo end-date trap, and how store-card deferred interest bites.
Avalanche vs Snowball: Which Debt Should You Pay Off First?
The avalanche method (highest APR first) is mathematically cheapest; the snowball (smallest balance first) is more motivating. See the exact math on 3 debts.
Why Paying More Than the Minimum Clears Debt Far Faster
Raising your monthly debt payment slashes both the months and the total interest. See how $100 more a month saves years and thousands on a $20,000 balance.
What DTI Do You Need to Get Approved for a Mortgage?
Most mortgages want a back-end DTI at or below 43%, but FHA, VA, and conventional loans approve higher with strong credit and reserves. See the real limits.
How to Lower Your DTI Before You Apply for a Loan
Lower your DTI fast by paying off small installment loans, knocking down card balances, and adding qualifying income. See exactly how much each move helps.
$X an Hour Is How Much a Year? The Hourly-to-Annual Math
$X an hour is how much a year? Multiply by 2,080 for a full-time year. See the chart, monthly and weekly pay, and how unpaid weeks change your true annual.
How to Combine Two (or More) Hourly Jobs Into One Annual Income
Working two hourly jobs? Convert each to annual gross, add them, and find your blended hourly rate. Worked example plus the tax and overtime gotchas.
Is My Net Worth Good for My Age? How to Judge Your Number
Wondering if your net worth is good for your age? Learn the fair way to benchmark it, why negative is normal early, and the savings rate that actually matters.
Net Worth vs Income: Why a Big Salary Doesn't Make You Rich
Net worth measures wealth you keep; income measures cash flow. See why high earners can be broke and how savings rate, not salary, builds real wealth.
The 'regular rate of pay': why a bonus must increase your overtime
Under the FLSA, overtime is paid on your regular rate, which includes nondiscretionary bonuses, not just base wage. See the formula and worked US examples.
Is overtime taxed more? How much of time-and-a-half you keep
No, overtime is not taxed at a special higher rate. See why time-and-a-half grows your check and how much of US overtime pay you actually take home.
What Is Actually Withheld From Your Paycheck? A Full Breakdown
See exactly what is taken out of a US paycheck: federal tax, FICA 7.65%, state tax, and pre-tax deductions like 401(k) and HSA, with worked dollar examples.
Effective vs Marginal Tax Rate: Why Your Real Rate Is Lower
Effective vs marginal tax rate explained with worked US examples, why your real rate is far below your bracket, and how to estimate take-home pay by hand.
Contribution Margin: What Each Sale Puts Toward Your Fixed Costs
Contribution margin is price minus variable cost - the dollars each sale puts toward fixed costs and profit. See the formula, the ratio, and worked examples.
Margin of Safety: How Much Cushion You Have Above Break-Even
Margin of safety is how far sales can drop before you hit break-even. See the formula, a worked example, and what a healthy cushion looks like in dollars and percent.
Straight-Line vs Declining Balance vs MACRS Depreciation: Which Method and When
Straight-line spreads cost evenly; declining balance front-loads it; MACRS is the IRS method for US taxes. See all three on the same asset, side by side.
How to Calculate Straight-Line Depreciation by Hand and in Excel
Straight-line depreciation = (cost - salvage) / useful life. See the formula, a full schedule, the Excel SLN function, and how to handle partial years.
How to find the original price from a sale price
Reverse a discount in seconds: find the original price from any sale price. Formulas, a quick-reference table, the percent-off trick, and tax-adjusted math.
Is 20% off actually a good deal?
Learn how to judge whether a percent-off sale is really a good deal: real-dollar savings, fake anchor prices, deal thresholds, and the math that cuts through hype.
What markup do I need to hit a target profit margin?
Want a 40% profit margin? You need a 66.67% markup, not 40%. Learn the exact formula to turn any target margin into the markup that gets you there.
Cost-plus pricing: how to price a product from your costs up
Cost-plus pricing builds your full unit cost, then adds a markup. See how to total materials, labor, and overhead, set a markup, and avoid the discount trap.
How to Do Percentages in Your Head, Fast
Learn the 10% trick, the 1% trick, and simple shortcuts to calculate percentages in your head fast - for tips, discounts, grades, and sales tax.
Real-Life Percentage Examples: Tips, Grades, Commission, and Tax
Worked percentage examples for everyday money: restaurant tips, test grades, sales commission, sales tax, and reversing a discount - all three question types.
Percentage Increase vs Decrease: Why the Math Is Not Symmetric
A 50% drop needs a 100% gain to recover, not 50%. Here is the exact recovery math, a clear table, and the simple rule behind why percentages do not cancel out.
How to Calculate Year-Over-Year (YoY) Growth, and When CAGR Is Better
Year-over-year growth is just percentage change between two periods. Here is the formula, worked examples, and why averaging YoY rates overstates real growth.
How to Convert Markup to Margin and Back: Formulas, a Reference Table, and Worked Examples
Convert markup to margin and back with two simple formulas, a full lookup table, and worked examples. See why a 50% markup is only a 33.33% margin.
Why Profit Margin Can Never Exceed 100% (and Markup Can)
Profit margin can never reach 100% because profit is part of the price. See why a 150% margin is impossible and how markup has no such ceiling.
Annualized ROI vs Total ROI: How to Compare Investments of Different Lengths
Total ROI ignores time, so a 3-year and a 1-year return are not comparable until you annualize. See the formula, worked examples, and when to use each.
How to Calculate Marketing ROI and ROAS the Right Way
ROAS measures revenue per ad dollar; true marketing ROI measures profit. See the formulas, break-even ROAS, and the revenue-vs-profit trap that fools advertisers.
How to Back Out Sales Tax From a Tax-Inclusive Total
Learn how to back out sales tax from a tax-inclusive total: the divide-by-(1+rate) formula, worked examples, the common mistake to avoid, and an Excel method.
Sales Tax Nexus for Online Sellers: Where You Have to Collect
Understand sales tax nexus for online sellers: economic vs physical nexus, origin vs destination sourcing, the 5 NOMAD states, and which rate to charge.
How much to tip everyone: a 2026 US tipping cheat sheet
A plain-English US tipping chart: how much to tip baristas, delivery drivers, hairdressers, hotel staff, movers, and more, with dollar examples for 2026.
Do you tip abroad? A tipping guide for US travelers
Tipping rules change country to country. A practical guide for US travelers: where 20% is rude, where rounding up is enough, and where service is included.
How VAT Works: The Multi-Stage Tax, Input Credits, and How It Differs From US Sales Tax
How VAT works as a multi-stage tax: businesses charge output VAT, reclaim input VAT, and remit the difference. A worked $600 supply chain and the US sales-tax contrast.
How to Add and Remove VAT From a Price: The Divide-Don't-Subtract Rule
How to add and remove VAT from a price: multiply to add, divide by (1 + rate) to remove. Worked examples at 20%, 17%, and 27%, VAT fractions, and by-hand math.
How to Calculate a Mortgage Payment, Step by Step
The exact formula for a monthly mortgage payment, explained in plain English with a worked example — plus the taxes, insurance and PMI the formula leaves out.
15-Year vs 30-Year Mortgage: Which Should You Choose?
A 15-year mortgage saves huge interest but costs more monthly; a 30-year frees up cash flow but costs far more long-term. A side-by-side example to help you decide.
What Is Compound Interest? A Simple Explanation
Compound interest is interest earned on your money AND the interest it already earned. See the formula, real examples, and why starting early beats saving more.
How Does Loan Interest Work?
Loan interest is charged on your remaining balance, so early payments are mostly interest. Here's how amortization works and four ways to pay far less.
How to Calculate a Car Loan Payment
Your car payment depends on the amount financed, the APR and the loan length. See the formula, a worked example, and why a longer loan is a costly trap.
How Much Car Can I Afford? The 20/4/10 Rule
The 20/4/10 rule: 20% down, a 4-year max loan, and total transport costs under 10% of gross monthly income. A worked example and when to bend it.
How to Pay Off Student Loans Faster: 7 Strategies
Pay extra toward principal, use the avalanche method, switch to biweekly, and more — 7 proven strategies to clear student loans years early and save thousands.