OneTabKit is a small, focused collection of free calculators and everyday utilities — the kind of thing you'd otherwise open five different tabs to figure out. Loan payments, a quick BMI check, converting a few units, formatting some JSON, spinning a wheel to make a decision — one tab, one site, no sign-up.
Every tool runs directly in your browser using plain JavaScript. When you type a number into the mortgage calculator or generate a password, that calculation happens on your own device — we don't have a server collecting what you type. The one exception is the Currency Converter, which fetches live exchange rates from a public, third-party rate provider so the numbers stay current.
OneTabKit is supported by advertising, which helps keep every tool free to use with no account, subscription, or paywall. See our Privacy Policy for details on how ads and cookies work on this site.
We're actively adding more tools. If there's something you wish existed, see the Contact page.