Personal finance guides
Short, plain-English explanations of the decisions behind the numbers, from extra mortgage payments to claiming Social Security. Every example is calculated with the same tested math as our calculators, and you can open each one with the inputs already filled in.
Mortgage & Home
Mortgage calculators →Home Equity Loan vs. HELOC: How Each Works and When to Use EachCompare home equity loans and HELOCs: how each works, the 80–85% CLTV rule that caps borrowing, costs, risks, and which fits your situation.5 min read15-Year vs. 30-Year Mortgage: Which Costs Less?Compare a 15-year and 30-year mortgage side by side: monthly payment, total interest, and when a 30-year loan with extra payments is the smarter middle path.3 min readHow Mortgage Amortization Works: Where Each Payment GoesWhy early mortgage payments are mostly interest, how an amortization schedule is built, and when your payments start paying down more principal than interest.3 min readHow Much House Can I Afford on My Salary?How lenders use the 28/36 rule to size your mortgage, what home price that works out to at common salaries, and why your comfortable budget may be lower.4 min readRent vs. Buy: How to Decide With Real NumbersRenting isn't throwing money away and buying isn't always an investment. See how rent, home prices, and investment returns decide which one builds more wealth.4 min readWhen Does Refinancing a Mortgage Make Sense?How to tell if a mortgage refinance pays off: the break-even point, the hidden cost of restarting a 30-year term, cash-out trade-offs, and when to skip it.3 min readHow Extra Mortgage Payments Actually Save You MoneyHow much interest extra mortgage payments really save (monthly, yearly, or a lump sum), with worked examples, and when paying down the mortgage isn't best.5 min readFHA vs. Conventional Loans: Which Costs Less Over 30 YearsFHA and conventional loans compared side by side: down payment, credit score, mortgage insurance that ends or doesn't, and the total cost over 30 years.5 min readIs 20% Down Still the Rule? What PMI Really CostsWhat private mortgage insurance costs, when it goes away, how to cancel it early, and whether it's worth waiting to save a 20% down payment before you buy.4 min read
Retirement
Retirement calculators →Catch-Up Contributions: Extra 401(k) and IRA Savings at 50+How 401(k) and IRA catch-up contributions work, the bigger age 60–63 catch-up, the new Roth rule for high earners, and what catching up is worth by retirement.3 min readHow Much Do I Need to Retire? A Step-by-Step EstimateEstimate your retirement number from spending, Social Security, and inflation, then see which changes, like saving more or retiring later, close a gap fastest.4 min readThe 4% Rule Explained: Does It Still Work?What the 4% rule for retirement withdrawals says, where it came from, how returns and spending change the result, and when to use a lower or more flexible rate.3 min readThe 401(k) Match: Free Money You Might Be Leaving on the TableHow 401(k) employer matching works, common match formulas, vesting schedules, and how much skipping part of your match can cost you by retirement.4 min readRoth vs. Traditional IRA: Which Saves You More in RetirementRoth vs. traditional IRA, explained with the math: why your tax rate now vs. in retirement decides it, plus income limits, withdrawal rules, and RMDs.4 min readWhen Should You Actually Claim Social Security?How your Social Security benefit changes if you claim at 62, full retirement age, or 70, the break-even ages, and how health and marriage change the answer.4 min read
Loans & Debt
Loans calculators →APR vs. Interest Rate: What's the Difference?Why a loan's APR is higher than its interest rate, how fees and points get folded in, how to compare offers with APR, and when APR points you the wrong way.3 min readHow Auto Loans Work: APR, Term, Trade-In, and TaxesWhat goes into the amount you finance on a car, how loan term and APR change the payment and total cost, negative equity, and rebate vs. 0% APR deals.4 min readHow Credit Card Interest Is Calculated (and How to Stop It)How card issuers turn your APR into a daily rate, why minimum payments take decades, how the grace period works, and the fastest ways to cut interest.3 min readAvalanche vs. Snowball: Which Payoff Method Saves MoreDebt avalanche vs. snowball on the same four debts: total interest, payoff dates, and when the method that costs a bit more is still the right choice.4 min readHow Loan Term Length Changes Your Total InterestWhy a longer loan term lowers your payment but raises total interest, with side-by-side numbers for 36- to 84-month auto loans and 15- vs. 30-year mortgages.3 min readRefinancing an Auto Loan: When It's Worth ItWhen refinancing a car loan saves money, how to compare a new rate and term with your current loan, fees to watch for, and when a lower payment costs more.3 min read
Savings & Investing
Investing calculators →APY vs. APR: How Compounding Changes Your Real RateWhat APY means on savings accounts and CDs, how it differs from APR, how compounding frequency affects it, and how to compare high-yield savings offers.3 min readHow Inflation Erodes Your Savings (and What to Do)See what inflation does to cash over 10 to 30 years, how to calculate your real return, and where to keep money so it holds its value without undue risk.3 min readCompound Interest: Why Starting Early Beats Investing MoreHow compound interest works, why ten years of saving in your 20s can beat thirty years starting at 35, the Rule of 72, and what the examples assume.4 min readDollar-Cost Averaging vs. Lump Sum InvestingInvest a windfall all at once or spread it out? How dollar-cost averaging works, what the research says about lump sum vs. DCA, and when each makes sense.3 min readHow to Set a Realistic Savings Goal and TimelineSet a savings goal you'll actually reach: size it, pick a realistic deadline, work out the monthly amount, and choose where to keep the money.4 min read
Taxes & Income
Taxes calculators →FICA Taxes Explained: Social Security and MedicareHow FICA payroll taxes work: the Social Security and Medicare rates, the wage base cap, the Additional Medicare Tax, what your employer pays, and what's exempt.3 min readStates With No Income Tax: What You Really SaveWhich states don't tax wages, how much more take-home pay that means versus income-tax states, and the sales, property, and payroll taxes that fill the gap.3 min readMarginal vs. Effective Tax Rate: What Actually Changes Your BillYour tax bracket isn't the rate you pay on all your income. How marginal and effective rates work, with a worked example and why a raise never cuts your pay.3 min readSalary vs. Hourly: What Changes When You SwitchHow to compare a salary with an hourly wage: converting pay, overtime rules, the real hourly rate of a salaried job, paid time off, and benefits to price in.4 min readHow Many Allowances Should You Claim on Your W-4? (The Form Changed)The W-4 no longer uses allowances. How the current form works step by step: two jobs or a working spouse, dependents, and when to add extra withholding.4 min read