Last updated: October 5, 2026
Useful Tools is an independent collection of free, fast utilities for everyday tasks: converting units and currencies, comparing time zones, working out loan and investment maths, formatting text, and more. It started as a personal toolbox because the common alternatives were slow, cluttered or asked for sign-ups to do a simple calculation.
What we offer
More than a dozen tools that each solve one job well: a unit and currency converter, a world time zone dashboard, finance calculators (compound interest, annuities, mortgages, NPV and IRR), a scientific calculator, a dictionary, a text toolkit with live typing speed, colour code conversion, URL and Base64 encoding, binary and hex conversion, a stopwatch and timer, a randomizer and word scrambler, a dice roller, and a sudoku generator.
Every tool loads instantly, works on phones and desktops, and needs no account.
How we keep results accurate
Unit conversions use the exact international definitions (for example, 1 inch = 2.54 cm and 1 pound = 0.45359237 kg). Time zones come from the IANA time zone database built into your browser, so daylight saving rules are applied correctly for any date.
Finance calculators use standard textbook formulas for present value, future value, annuities, amortisation, NPV and IRR. Each formula is shown on the page so you can check the working yourself.
If you ever find a result that looks wrong, please tell us through the contact page and we will fix it.
Your privacy
Calculations run directly on your device. What you type into a tool is not sent to us. The site is supported by advertising; see our Privacy Policy for details on cookies and ads.
Get in touch
Suggestions for new tools, bug reports and general questions are welcome on our contact page. Please also read our Privacy Policy and Terms of Use.