Privacy policy

In short: what you type into a calculator never leaves your device, and this site doesn't collect personal information itself. A few small ads from Adsterra pay for the site, and they may use cookies.

Last updated: 3 October 2026

What you enter stays on your device

All calculations run in your web browser. Measurements and other numbers you type into a calculator are never sent to a server, stored or logged by this site. The ads can't see them either (see below).

No accounts or analytics

• There are no user accounts or sign-ups.
• The site itself sets no cookies.
• There are no analytics, tracking pixels or social media widgets.
• Apart from the ads, every file the site uses, including fonts, comes from this site.

Advertising

The site shows at most two small ads on a calculator page, provided by Adsterra. There are no pop-ups, no redirects and no ads between the form and your result.

• Sealed off from the page. Each ad loads in its own small frame. That frame is isolated from the calculator: it can't read what you type or what is saved in your browser for this site, and it can't take you to another page unless you click the ad.
• What the ad network receives. When an ad loads, your browser contacts Adsterra and the advertisers it works with. As with any website you visit, they receive technical information such as your IP address, browser and device type, and the address of the page. They may set or read cookies to choose ads, limit how often you see the same one, count views and clicks, and prevent fraud. That is covered by Adsterra's privacy policy.
• Only when visible. Ads load only when they scroll near the screen.

Your choice

If your device's time zone is in the European Union, the EEA, the UK or Switzerland, no ads load until you choose Allow ads in the bar at the bottom of the page.

Anyone, anywhere, can change their choice at any time with Ad choices at the bottom of every page. Choosing No thanks stops ads loading on this site in that browser. Ad blockers work too, and the calculators work exactly the same without ads.

What is saved in your browser

Two settings are remembered in your browser's local storage: whether you last used US or metric units, so the next calculator opens the same way, and your ad choice, if you make one. They are stored only on your device and are never sent to us. You can remove them at any time by clearing this site's data in your browser settings.

Hosting

The site is hosted on Cloudflare. Like any web host, Cloudflare processes technical information such as IP addresses when delivering pages, for example to keep the service secure and reliable. That processing is covered by Cloudflare's privacy policy. This site doesn't use that information to identify or profile visitors.

Changes to this policy

If anything changes how data is handled, this page will be updated before that change goes live.

Contact

Questions about privacy can be raised by opening an issue on GitHub.