Everyday calculators

Daily math, unit conversion and loan estimates

17 tools

Percentage Calculator (percent of, percent change, reverse percentage)Work out X% of Y, what percent X is of Y, the percentage change from A to B, a value after a ±X% change and the original value before it — exact decimals, with clear errors for division by zero.
Tip Calculator (tip percentage, tax, split the bill)Enter the bill and a tip percentage to get the tip, the total and what each person pays, exact to the smallest unit — with tip on the pre-tax amount and optional rounding up of each share.
Bill Splitter (equal, by shares or by percentage)Split a total between people equally, by shares (2 : 1 : 1) or by percentage, optionally in round units such as 10 or 100, with an explicit, deterministic split of the remainder.
Unit Converter (length, weight, area, volume, speed)Convert meters, inches, pounds, gallons, km/h and more between length, weight, area, volume and speed units using exact definitions. Type in either box to convert both ways.
Temperature Converter (Celsius, Fahrenheit, Kelvin)Convert between Celsius (°C), Fahrenheit (°F) and kelvin (K). Type in any box to get the other two units; temperatures below absolute zero are rejected.
Age Calculator (exact age and next birthday)Calculate exact age in years, months and days from a date of birth, plus days since birth and days until the next birthday. Choose how Feb 29 birthdays count in common years.
Date Difference Calculator (days between dates)Find how many days, weeks and months lie between two dates. Choose whether the start date counts; leap years and month ends are handled correctly.
Working Hours Calculator (breaks and overnight shifts)Calculate hours worked from start and end times minus breaks. Handles overnight shifts such as 22:00–06:00, totals several shifts and exports a CSV.
Hourly, Monthly and Annual Pay Converter (with your own assumptions)Convert gross pay between hourly, daily, weekly, monthly and annual amounts. Hours per day, days per week and weeks per year (or days per month) are editable and shown with the result.
Mortgage Payment Calculator (level payments with amortization schedule)Calculate the monthly payment, total paid and total interest of a level-payment loan from the amount, annual rate and term, with a full amortization schedule (CSV) and a 0% rate case.
Installment Payment Calculator (fees and APR estimate)From the principal, number of installments, interest method (annual rate on the balance or flat rate), one-time and per-installment fees: the installment, total paid, interest and fees, plus a solved APR.
Compound Interest Calculator (contributions, compounding, yearly chart)Project the balance and interest from a principal, annual rate, period, compounding (yearly to daily) and monthly or yearly contributions, with a year-by-year chart and table. Assumes a fixed rate; not investment advice.
Savings Goal Calculator (how much to save each month)Work out how much to save each month to reach a goal from the target, what you have saved, a deadline (months or a date) and an assumed return, with a weekly figure and the projected balance. Not investment advice.
Appliance Electricity Cost Calculator (kWh and cost)Estimate the energy use (kWh) and electricity cost of an appliance from its wattage, hours of use per day, number of days and your price per kWh.
Recipe Serving Scaler (adjust ingredient amounts)Scale every ingredient of a recipe to the number of servings you need. Fractions such as 1/2 or 1 1/2 work, and units like g, cups or tbsp are kept as written.
BMI Calculator (WHO and national cut-offs)Calculate your BMI from height and weight and see the WHO adult category alongside the Japanese, Taiwanese and Chinese cut-offs. Metric and imperial units; a guide, not a diagnosis.
Online Click Counter (tally counter)Count with clicks, taps or the keyboard. Set the step and optional lower and upper limits; the count is saved automatically in your browser.

More tools are being released step by step.