Finance Formulas with Calculators and Worked Solutions
This section collects the formulas used in corporate finance, investing, accounting and personal finance courses, each on its own page with the formula written out, a plain-English definition of every variable and a calculator that solves it with your numbers. Every calculator prints its working step by step, so you can check a homework answer, follow how a spreadsheet function reaches its result, or copy the method into a report.
The formulas are grouped the way textbooks teach them: the time value of money (present and future value, annuities, NPV and IRR), loans and amortization, returns and investment analysis (ROI, CAGR, CAPM, WACC, bond pricing and yield), financial statement ratios, depreciation methods, and break-even and leverage analysis for business decisions. Type in the search box to jump straight to a formula.
Each page opens with a worked default example so you can see a complete solution before entering your own figures. The calculations were checked against numpy-financial, SciPy and the published examples for the equivalent spreadsheet functions (PV, FV, PMT, NPV, IRR, MIRR, DB, DDB, SYD and others). Everything runs in your browser; nothing you type is sent anywhere.
90 formulas
Jump to: Time value of money · Loans · Returns and investing · Financial ratios · Depreciation · Break-even, margins and leverage
Time value of money (26)
Present and future value, annuities, perpetuities, NPV, IRR, payback, interest-rate conversions and doubling time.
Loans (6)
Loan payments, balloon and interest-only loans, remaining balance, payoff time and a full amortization schedule.
Returns and investing (25)
ROI, CAGR, average returns, dividends and valuation, CAPM, WACC, beta, risk-adjusted ratios and bonds.
Financial ratios (21)
Liquidity, leverage, profitability and efficiency ratios from the balance sheet and income statement, plus DuPont analysis.
Depreciation (5)
Straight-line, declining balance, double declining balance, sum-of-the-years'-digits and units of production, each with a schedule.
Break-even, margins and leverage (7)
Break-even point, contribution margin, markup versus margin, and operating, financial and combined leverage.
Frequently asked questions
- Are these finance calculators free?
- Yes. Every formula page and calculator is free to use, with no sign-up.
- Do the calculators show the working?
- Yes. Each result comes with the formula, your numbers substituted in and every intermediate value, in the order a textbook solution would use.
- How accurate are the results?
- The calculations were validated against numpy-financial, SciPy and spreadsheet reference examples on more than 600 test cases.
- Which formula do I need to value an investment project?
- Start with net present value (NPV). Use IRR or MIRR to express the return as a rate, the profitability index to rank projects when capital is limited, and the payback period for a quick liquidity check.
- What is the difference between APR, APY and the effective annual rate?
- APR is a nominal annual rate; APY and the effective annual rate are the same thing, the rate actually earned or paid over a year once compounding is included.
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Last reviewed: September 26, 2026. 90 formulas, each validated against numpy-financial, SciPy or published spreadsheet examples.
