Precision instruments, not guesswork
Every calculator, one place
Straightforward calculators with the formula and the reasoning laid out, so you can check the number instead of trusting it blindly.
Browse all calculators14 Calculators
Sample readout
22.9 × 1.75²
70.1kg
Every calculator on this site ships a readout like this — the formula, the numbers plugged in, and the result.
Why this is different
Shows its work
Every result comes with the formula and the exact numbers plugged in, so you can verify it instead of taking it on faith.
Five languages
English, Korean, Japanese, German, and Spanish — each one written and checked on its own, not bolted on with machine translation.
Ads stay out of your way
Ad placements are banned next to inputs and buttons by policy, so you never tap an ad by accident while you're calculating.
Browse by category
01Health
5- BMI CalculatorEnter your weight and height to calculate your Body Mass Index (BMI), a quick screening measure used worldwide to estimate whether your weight falls in a healthy range for your height.Shows its formulaLast updated 2026-08-11
- Body Fat Percentage CalculatorEnter your height, neck, waist, and (if female) hip measurements to estimate your body fat percentage using the U.S. Navy circumference method — no calipers or scans required, just a tape measure.Shows its formulaLast updated 2026-08-11
- TDEE CalculatorEnter your sex, age, weight, height, and activity level to estimate your Total Daily Energy Expenditure (TDEE) — the number of calories your body burns in a typical day, including movement and exercise.Shows its formulaLast updated 2026-08-11
- Due Date CalculatorEnter the first day of your last period and your average cycle length to estimate your due date, trimester milestones, and when your pregnancy reaches full term. This is a general estimate meant to support, not replace, care from your doctor or midwife.Shows its formulaLast updated 2026-08-11
- Ovulation & Fertile Window CalculatorEnter the start date of your last period and your typical cycle length to estimate your ovulation date, fertile window, and next expected period.Shows its formulaLast updated 2026-08-11
02Finance
3- Loan Payment CalculatorEnter your loan amount, interest rate, and term to estimate your monthly payment and total interest over the life of the loan.Shows its formulaLast updated 2026-08-11
- Compound Interest CalculatorEstimate how an initial investment plus monthly contributions can grow over time with compound interest.Shows its formulaLast updated 2026-08-11
- Retirement Savings CalculatorEstimate how your current savings and monthly contributions could grow by retirement — and what that amount is actually worth once inflation is factored in.Shows its formulaLast updated 2026-08-11
04Everyday
5- Date Difference CalculatorPick a start date and an end date to see how much time separates them — in days, weeks, approximate months and years, and in working days once weekends are taken out.Shows its formulaLast updated 2026-08-11
- Age CalculatorEnter a date of birth and a reference date to get an exact age in completed years, months and days, along with the total number of days lived and the date of the next birthday.Shows its formulaLast updated 2026-08-11
- Unit ConverterPick a category, type a value, and choose the units to convert between. Length, weight, and volume use exact ratio factors; temperature uses its own offset formula.Shows its formulaLast updated 2026-08-11
- Tip CalculatorEnter the bill, the tip percentage, and how many people are sharing it. The calculator adds the tip, divides the total, and can round up either the total or each share.Shows its formulaLast updated 2026-08-11
- Discount CalculatorEnter the original price and up to two discounts to see the final price, how much you save, and the real effective discount once the second offer is applied to the already-reduced price.Shows its formulaLast updated 2026-08-11