About Us

We build free calculators and converters for the questions people actually type into a search box: what is 15% of 240, how many days until a date, what does my mortgage cost each month, how many inches is 50 cm.

What we believe

A calculator should give the right answer, show how it got there, and get out of the way. Every tool on this site shows its formula, walks through a worked example and explains the assumptions behind it, so you can check the result instead of just trusting it.

Private by design

The calculations run in your browser. The numbers you type are not sent to our servers, and image and text converters process files locally. We only record anonymous usage counts, such as whether a tool ran successfully, so we can find and fix broken tools.

How we keep results accurate

• Every calculator is tested against known values and against invalid input, such as empty fields, negative numbers, zero and very large values.
• Health and finance tools use published, widely accepted formulas and name them on the page.
• Where a result depends on rules that change, such as tax rates, we ask you to enter the rate instead of guessing it for you.

Important notice

Health, pregnancy and finance calculators give estimates for general information. They are not medical, legal, tax or financial advice. Please speak to a qualified professional before making decisions that matter.

Get in touch

Found a mistake or want a calculator we do not have yet? Use the contact page. We read every message.