Free · No sign-up · Runs in your browser
Finance calculators
that show
their work.
Most calculators hand you a number and hide the arithmetic. Every tool here shows the formula, states its assumptions, and gives you the full schedule underneath — so you can check the answer instead of trusting it.
- Calculators
- 15
- Categories
- 6
- Sign-up required
- None
Browse by need
Grouped by the question
you are actually asking.
15 calculators published so far. A category appears here once it holds a tool whose maths is tested and whose sources are cited — not before.
- Mortgage & Home Work out payments, affordability, amortisation and the cost of paying early. 2 tools
- Loans & Debt Payments, interest, amortisation and payoff strategies for any fixed-rate loan. 4 tools
- Saving & Investing Compound growth, contributions, returns, inflation and goal planning. 4 tools
- Salary & Pay Convert pay periods, compute overtime, raises and take-home pay. 1 tool
- Business Margins, markup, break-even, ROI and business financing. 2 tools
- Everyday Money Percentages, discounts, budgets, savings goals, net worth and inflation. 2 tools
How a calculator page works
An answer you can check, in three parts.
-
You get the number
Type your figures and the result updates as you go. Nothing is submitted and there is no calculate button to hunt for.
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Then the working
The formula it evaluated, a worked example with real values, and the full schedule row by row — not a summary of it.
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And what it assumes
Every tool states what it does not model, and cites the law or convention behind any rule it applies, with the date checked.
Pick a question
Start with the one you came for.
Every tool is free, needs no account, and runs entirely in this browser tab.