Financial calculators that show the time value of money
Investing, debt, pricing and business decisions, with interactive charts, a plain-language reading of every result and a PDF report.
PersonalCalcs exists so that anyone can see how time and interest change money before deciding: investing, borrowing, hiring or setting a price. The calculators are free, show the formulas and assumptions behind each number and explain every result in plain language. They are educational: they do not make investment recommendations or replace advice from a qualified professional.
Compound interest with monthly contributions
What comes from your pocket, what comes from interest and what the total is worth in today’s money after inflation. Change the term or the rate and watch the curve pull away.
Run the compound interest calculator →
When your savings can pay your income
Follows your savings while you contribute and after you stop, and compares them with the contribution needed to reach the goal and keep the income to the end of the horizon.
Calculate financial independence →
The shortest way out of debt
Compares avalanche, snowball, paying only the minimum and switching to a cheaper loan: when each path clears the balance and how much interest it costs.
Build the payoff plan →
Selling price and break-even
How many monthly sales cover fixed costs, at the suggested price and at your current price, and how much profit is left at each volume.
Calculate the selling price →
Charts that explain the result
Every calculation comes with interactive charts and a short text that says, in plain language, what the numbers mean.
The same contributions at different rates: the gap between the lines is what a rate difference does over 20 years.
The wealth of buying against renting and investing the difference, year by year, with the home’s appreciation.
How much of each sale goes to cost, taxes, fees, fixed costs and profit.
From your numbers to a PDF report
Use search or the menus at the top: personal finance, investing, work, business and startups.
Every page opens with a worked example. Results, charts and the explanation update instantly.
Download the summary or the full report, with inputs, formulas, assumptions, sources and the rules review date.
Start with your first simulation
Free, with no sign-up. The values you type stay in your browser. Corrections and ideas for new calculators help improve the site for everyone.
Contribute: Report an errorSuggest a calculator
Standard financial formulas · compound interest · present and future value · NPV and IRR · amortization · break-even
Important notice: PersonalCalcs calculators are educational tools that produce estimates from the data you enter and from standard financial formulas. Results are not investment, tax, legal or accounting advice and are not an offer or recommendation to buy or sell any security or financial product. PersonalCalcs is not a bank, broker or licensed financial adviser. Rates, taxes and rules vary by country and change over time: check with an official source or a qualified professional before making decisions. By using this site you agree to the Terms of Use.
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