About KitWren

KitWren is one place for the small jobs that come up every day: working out a percentage or a loan repayment, converting units or currency, shrinking a PDF, resizing a photo, formatting some JSON or putting together an invoice. Instead of searching for a different website each time, you can search here in plain words and go straight to the right tool.

What we believe

• Useful first. Every tool should work properly, explain its answer and handle mistakes gracefully.
• Free and open to everyone. No account is needed to use the tools. The site is supported by advertising and clearly labelled partner links, never by paywalls.
• Private by default. Wherever possible, tools run in your browser, so your files and data stay on your device. When a tool does need our server, the page says so.
• Honest. We don’t show fake usage numbers, fake reviews or misleading download buttons.

Accuracy

We test our calculators against published formulas and examples, and each page shows the formula it uses. Financial, tax, health and legal results are estimates for information only — please confirm important decisions with a qualified professional or the official source.

Get in touch

Found a bug, a wrong answer, or a tool you wish existed? Email hello@kitwren.com. You can also browse every tool or read our privacy policy.