Calculators
Seven free, instant, private calculators for everyday math. Percentage, age, discount, loan, salary, BMI, and unit conversion — all run in your browser.
Percentage Calculator
Calculate percentages, percentage increases and decreases, and find what percent one number is of another.
Age Calculator
Calculate your exact age in years, months, and days from any birth date.
Discount Calculator
Calculate the final price after a discount, the savings amount, or the discount percentage.
Loan Calculator
Calculate monthly loan payments, total interest paid, and total cost.
Salary Calculator
Convert between hourly, daily, weekly, monthly, and annual salary.
BMI Calculator
Calculate your Body Mass Index (BMI) from height and weight.
Unit Converter
Convert between units of length, weight, and temperature.
About these calculators
Every calculator on this page runs entirely in your browser using JavaScript. When you type a value into any input field, the result is computed instantly on your device — no server round-trips, no waiting, no data sent anywhere. This makes the calculators fast, private, and free to operate.
All formulas use internationally recognized standards. The loan calculator uses the standard amortization formula taught in finance courses. The BMI calculator uses the World Health Organization category ranges. The unit converter uses exact conversion factors (for example, 1 inch = 2.54 centimeters exactly, per the international yard and pound agreement of 1959).
Each calculator has its own page with detailed explanations, step-by-step instructions, and a FAQ section. Pick a calculator above to get started.