About CalcWren
Boring tools, built well. Fast, free, and private by design.
CalcWren is an independent collection of utility tools: calculators, converters, formatters and document templates. Calculator arithmetic and file conversion run locally in your browser. Domain lookups contact external registries, feedback is sent through Web3Forms, and advertising loads from Google. Our privacy policy explains these connections.
Why these tools
Most utility sites bury simple answers under pop-ups, sign-up walls and upload queues. CalcWren tools work without an account. Local calculations can continue offline once their required code has loaded; domain lookups, feedback and external preview assets need a connection. We use regression tests and review the sources behind tax and finance calculations when updating them.
How the site is funded
The site is free to use and includes Google AdSense advertising to help cover running costs. Using the tools does not require an account or payment. Advertising can involve cookies and technical request data, as explained in the privacy policy.
Feedback
Found something wrong? Every tool page has a Report a problem button, and the feedback form is read by a human. Bug reports with examples get fixed first.