Calculators and converters

Percentages, VAT, discounts, interest, unit conversions, cooking measures and more. Type the numbers, get the answer and see how it was worked out.

  • Free
  • No sign-up
  • Runs in your browser

Popular searches

Ready-made pages for the most common conversions, calculations and formats.

Unit converter

Cooking measures converter

Percentage calculator

VAT calculator

All tools in this category

Percentage calculatorPercent of a number, percentage change, increase and decrease, and reverse percentages. Unit converterConvert length, weight, volume, temperature, speed and more between metric and imperial units. VAT calculatorAdd VAT to a price, or find the price before VAT from a total. Aspect ratio calculatorFind the aspect ratio of a size, and the width or height that keeps it when you resize. Break-even calculatorHow many units must you sell to cover your costs, and to reach a profit target? Compound interest calculatorSee how a starting amount and monthly deposits grow with compound interest. Discount calculatorPrice after a discount, how much you save, and the original price from a sale price. File size converterConvert bytes, KB, MB, GB, TB and KiB, MiB, GiB, and estimate the transfer time. Margin and markup calculatorCalculate margin, markup, profit and price, and convert between margin and markup. Pixels, rem, em, points and millimetresConvert between px, rem, em, pt, pc, mm, cm and inches, with your root font size. Cooking measures converterConvert cups, spoons, grams, ounces and millilitres, with oven temperatures. Electricity cost calculatorWhat does an appliance cost to run, from its power, hours of use and the price per kWh? Fuel cost calculatorHow much will the fuel for a trip cost, in total and per person? Rule of three calculatorFind the missing number in a direct or inverse proportion. Split an amount into partsDivide an amount into equal parts or in proportion to shares, with cents that add up exactly. Split the bill calculatorDivide a bill between any number of people, with an optional tip.

What you can do here

A good calculator does more than print a number. It states the formula, shows the steps and lets you change one input to see what happens. That is how these calculators work: for every result you also see the calculation, so you can check it, learn from it and reuse it in a spreadsheet.

Whether you need to add VAT to a price, work out a discount, convert 100 grams of flour into cups or find the percentage change between two numbers, you will find a tool here. Everything is calculated in your browser, so the figures you enter, from invoices to budgets, are never stored or shared.

  • Everyday maths: percentages, rule of three, discounts, splitting a bill or an amount.
  • Money: VAT, margin and markup, break-even, compound interest, fuel and electricity costs.
  • Conversions: units, file sizes, cooking measures and CSS units.
  • Design: aspect ratio and pixel, rem and em conversions.

Frequently asked questions

Are the results exact?
The calculators use standard formulas and display rounded results. Where rounding matters, such as VAT on invoices, the tool states how it rounds.
Can I see how the answer was calculated?
Yes. Most tools show the formula and the steps next to the result.
Is my financial data stored?
No. Everything is calculated in your browser and nothing is sent or saved.
Do the calculators work for any currency?
Yes. Amounts are just numbers, and tools that show a currency let you pick a symbol or none.
Can I use them for professional work?
They are fine for estimates and everyday use. For tax filings or contracts, confirm the figures against official guidance or a professional.