What this site is
ToolNest is a library of 56 free web tools organised into 8 categories, finance, health and fitness, date and time, fun and text, plus Air Quality in Cigarettes, a live tracker with dedicated pages for 115 cities. Each tool solves one everyday problem well, whether that is working out a loan payment, finding your exact age, checking how strong a password is or seeing whether today's air is safe to exercise in.
How the tools work
Every calculator is implemented in plain JavaScript and runs entirely inside your web browser. When you type a number or pick a date, the processing happens on your own device. Nothing is uploaded, stored or logged by us. The air-quality pages call the public Open-Meteo API directly from your browser, so your searches and location never pass through our servers either.
We deliberately avoid heavy frameworks and trackers. Pages are pre-rendered as static HTML so they load quickly on slow connections and older phones, and every calculator ships with automated tests that must pass before a new version is published.
How the site stays free
ToolNest is supported by advertising served through Google AdSense. Ads are kept away from the tool interface so they never get in the way of the task you came here to do. We do not sell data, run paywalls or require accounts. You can read more about how advertising cookies work in our Privacy Policy and Cookie Policy.
Accuracy
We test each tool carefully and document the formula on every page, but calculators are provided for general information only. Results for health (such as BMI or caffeine) or finance (such as loan payments) are estimates and should not replace advice from a qualified professional. Air-quality figures come from an atmospheric model and can differ from local monitors. See the Terms of Service for details.
Suggestions and bug reports
New tools are added based on what people ask for. If something does not work as expected, or you would like to see a new utility, please visit the contact page.