Quick answers to everyday math
Loan payments, tips, ages, oven temperatures, file sizes — pick a calculator, type your numbers, and the answer appears as you type. Free, fast, and nothing you enter leaves your browser.
- Finance Loans, interest, tax and everyday money math 22 calculators
- Health & Fitness Body metrics, calories, hydration and training 12 calculators
- Math Percentages, fractions, geometry and statistics 11 calculators
- Unit Conversions Length, weight, temperature and other units 10 calculators
- Data & Storage File sizes, bandwidth and transfer times 5 calculators
- Date & Time Ages, durations, deadlines and countdowns 7 calculators
- Cooking Recipe scaling, oven temperatures and kitchen measures 7 calculators
- Everyday Fuel, electricity, paint, flooring and more 11 calculators
- Developer API pricing, cloud costs, SaaS metrics and freelance rates 15 calculators
Most used
- Age Calculator Exact age in years, months and days
- BMI Calculator Body mass index and healthy weight range
- Calorie Calculator Daily calories to maintain, lose or gain
- Compound Interest Calculator Future value and interest at any frequency
- Credit Card Payoff Calculator Time and interest to clear a card balance
- Cups to Grams Converter Cups to grams for common ingredients
- Date Difference Calculator Days, weeks and months between two dates
- Freelance Rate Calculator Hourly and day rate from target salary
- Fuel Cost Calculator Fuel cost for any trip
- Length Converter Meters, feet, inches, miles and more
- LLM API Cost Calculator Compare monthly spend across LLM APIs
- Loan Calculator Monthly payment and total interest cost
- Mortgage Calculator Monthly payment and lifetime interest
- Oven Temperature Converter Celsius, Fahrenheit, gas mark and fan
- Payment Gateway Fee Calculator Compare Stripe, PayPal, Paddle, Lemon Squeezy
- Percentage Calculator The three percent questions, answered
- Pregnancy Due Date Calculator Due date from LMP, conception or IVF
- Retirement Savings Calculator Nest egg from your balance and monthly saving
- Shoe Size Converter US, UK and EU sizes plus foot length
- Tip Calculator Work out the tip and split the bill
Why this site exists
Most quick calculations end up in a phone calculator app, a search box, or a spreadsheet that deserves better. Each tool here does one job with the formula spelled out underneath, so you can check the working instead of trusting a black box. Where a calculation has an official or widely accepted formula — loan amortization, BMI, the 1959 inch — that is the one used, with the source named on the page.
Everything runs in your browser. There are no accounts, and the numbers you type are never sent to a server. If something looks wrong, tell us — reports are read and acted on.