Financial calculators that show their work.
Free tools for the money decisions that matter. Every result comes with the formula, each step worked through with your own numbers, and a plain-English explanation.
All calculators
MortgageMonthly payment, total cost of the loan, and a full amortization scheduleRent vs. buyThe break-even year for buying instead of rentingCredit card payoffYour debt-free date at any monthly paymentStock returnsGrowth with dividends, regular investing and feesBond price & yieldPrice, yield to maturity and duration for any couponMutual fund feesWhat an expense ratio really costs over decadesAnnuityPayout, present value and future valueCompound interestSavings growth with regular deposits
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Guides
How amortization actually works8 min · MortgageAPR vs. APY, and why your card quotes APR5 min · Credit cardsBond price vs. yield, with one worked example6 min · BondsWhat an expense ratio costs over 30 years4 min · FundsEvery answer shows its work
The formula, your numbers substituted into it, and a numbered path from inputs to result — so you can check it or learn it.
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Checked and dated
Each calculator names its method and review date. Educational tools, never financial advice.