Calculators

Straightforward math with visible formulas.

Each calculator states what it computes and which inputs it needs.

Results update as you type so you can check a figure without a separate submit step.

Percentage CalculatorFind X percent of Y, what percent one number is of another, percent change, and percent difference. Math stays in this tab.
Discount CalculatorWork out sale prices from an original amount and a discount percent. Optional tax applies after the discount, all in the browser.
Age CalculatorCalculate exact age in years, months, and days from a date of birth. See days lived and the next birthday, computed locally.
Date Difference CalculatorMeasure the span between two calendar dates in days, weeks, months, and years. Optionally include the end date in the count.
Average CalculatorPaste a list of numbers and get the mean, median, sum, count, min, and max. Stats compute in your browser from the values you type.
Ratio CalculatorSimplify a ratio to lowest terms or solve a missing value in A:B = C:D. Proportion math runs locally in this browser tab.
Compound Interest CalculatorProject a balance with compound interest, yearly contributions, and yearly, quarterly, monthly, or daily compounding in this tab.