Calculators

Body mass index with Chinese adult thresholds

Equal payment vs equal principal, side by side

Length, weight, area, volume, data and temperature

Exact age in days plus next birthday countdown

Difference in days, weeks and calendar months

Shares, percentage change and relative difference

Original price, discount and final price

Monthly pay to hourly, daily and annual

Monthly income tax using the cumulative withholding method

Enter a tax-inclusive amount and a rate to split it into the net price and the tax portion. The calculation divides the gross price by 1 + rate, then reports the net, the tax and the gross, all to two decimals.

Estimate a fixed-rate mortgage with equal monthly installments: the payment stays the same while early payments are mostly interest. Enter the loan in units of 10,000, the annual rate and the term; the monthly rate is the annual rate divided by 12 and the term is years × 12.

Estimate your basal metabolic rate with the Mifflin–St Jeor equation, multiply it by an activity factor to get daily calories burned, and see a fat-loss reference set 400 kcal below that. The equation uses the male variant, so treat the output as an estimate.

Turn a distance and total time into average pace per kilometre, speed in km/h and the time a 5 km split would take. Pace is total time divided by distance, so hills, intervals and a fast start are not accounted for.

Estimate how a lump sum grows with annual compounding: the final value is the principal multiplied by (1 + annual rate) raised to the number of years. You get the balance, the interest earned and the multiple, with no fees or extra contributions.

Count business days between two dates. Each day from start to end is checked and only Monday to Friday count, with both endpoints included. Public holidays and make-up workdays are not detected, and the calendar-day total is shown too.

Add or subtract a number of days from a date and see the resulting date with its weekday. Counting is by calendar day, so a negative number goes backwards, and month ends, year ends and leap years are handled by the date itself, so treat the output as a reference date.

Work out a tip from the bill and a percentage, then split the total evenly between diners. Tip = bill × percent, total = bill + tip and each share = total ÷ people, with no adjustment for pre-tax versus post-tax tipping customs.

Enter a date to see which weekday it falls on, which week and day of the year it is, and whether that year is a leap year. Week numbers use a simple rule that starts on 1 January with seven-day blocks, so they can differ from ISO week numbers.

Check a US or UK size chart, a furniture listing, or a screen spec that only quotes inches. Type the centimetre figure and read the inch value as you go, so you can compare numbers while shopping instead of reaching for a calculator.

Monitors, pipe diameters, and height figures from abroad are often given in inches. Enter the inch value to get centimetres, so you can judge the real size against a spec sheet before buying.

Protein powder listings, American gym plates, and overseas shipping forms all use pounds. Convert kilograms to pounds before you order or check in a suitcase, so the weight limit doesn't catch you at the counter.

US recipes, imported product labels, and overseas sports stats give weight in pounds. Convert to kilograms so the number means something on a kitchen scale or a bathroom scale.

Race entries abroad, running apps set to miles, and overseas car rentals all speak in miles. Convert kilometres before you sign up or compare distances, whether it's a 10K or a full marathon.

Speed limit signs in the US, treadmill displays, and used-car odometers all count in miles. Convert them to kilometres to judge the real distance, or to plan fuel and time before a road trip abroad.

Tell a friend abroad what the weather is like, set an oven from an English recipe, or fill in a form that expects Fahrenheit. Enter Celsius and get the Fahrenheit figure, including below zero.

US forecasts, English recipes that call for a 350 °F oven, and thermometers sold abroad all read in Fahrenheit. Convert to Celsius so you know what to wear or which oven setting to pick.

Ceiling heights in foreign listings, dive depths, and aircraft altitudes are given in feet. Convert metres before you compare, whether you're checking a flat abroad or reading a spec sheet at home.

Listings abroad, US rental ads, and property tax bills quote floor area in square feet. Convert square metres before comparing, especially when you're sizing up a flat in another country.

Data plans, cloud storage, and game installs are sold in GB, but limits are often enforced in MB. Convert with the 1024-based convention to see how much room you actually have.

Timesheets, shift rosters, and lesson lengths are often recorded in minutes, while people quote hours. Convert 1.5 hours to 90 minutes before filling in a form or checking a payslip.