Finance Calculators

Finance Calculators cover the numbers behind the biggest personal financial decisions: mortgages, loans, retirement savings, taxes, and investment returns. Homebuyers use them to compare mortgage offers and see full amortization schedules; investors use them to model compound growth, bond pricing, and inflation-adjusted returns; freelancers and founders use the startup tools to plan runway, break-even revenue, and valuation. Every calculator runs the same math as our REST API, with no sign-up and no data stored — they're built for exploring the numbers behind a decision, not as a substitute for professional financial advice.

Loans & Property

Use these when you’re evaluating a mortgage, comparing loan offers, or sizing up a property purchase.

Investing & Markets

Model returns, pricing, and portfolio decisions across stocks, bonds, and retirement accounts.

Compound Interest Calculator
See how a balance grows over time with compounding interest, year by year.
NPV Calculator
Calculate net present value, internal rate of return and payback period for a series of c…
Bond Price Calculator
Price a fixed-rate bond and see its duration and yield to maturity.
Share Price Calculator
Estimate a stock's intrinsic value from its expected dividend using the Gordon Growth Mod…
Inflation Adjusted Return Calculator
See what your investment return is really worth once inflation is accounted for.
Currency Converter
Convert between currencies using live exchange rates.
US Treasury Yield Curve
Live US Treasury yields across 9 maturities from FRED, with yield curve inversion detecti…
Benchmark Rate Calculator
Compute compounded or simple SOFR, €STR, or SONIA averages for any interest period. Daily…
S&P 500 Historical Returns
Annual S&P 500 returns from 1928 to present — CAGR, volatility, best/worst year, and the…
VIX Historical Volatility Calculator
Look up the CBOE VIX for any trading day since 1990 — percentile rank, volatility regime,…
CPI Purchasing Power Calculator
Convert any dollar amount between any two years using official US BLS CPI-U data (1913–20…
Price Indexation Calculator
Index a contract value between any two periods using Eurostat HICP — EU & UK official inf…
Black-Scholes Options Pricer
Price European call and put options and calculate the full set of Greeks using the Black-…
Portfolio Rebalancing Calculator
Calculate exactly how much to buy or sell to restore your target asset allocation.
Kelly Criterion Calculator
Calculate the optimal bet or position size using the Kelly Criterion formula.

Salary & Tax

See what actually lands in your bank account after tax, or what an employee really costs to hire.

Retirement & Tax Planning

Plan withdrawals, savings targets, and everyday tax and invoicing calculations.

Startup & Business Planning

Runway, revenue, and valuation tools for founders and freelancers running the numbers on a business.

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