Privacy and referral links

Nothing that identifies you. There are no accounts, no sign-up forms and no advertising trackers on this site.

The calculator runs in your browser. Your exact figures stay there unless you create a share link, in which case they are part of that link's address and nothing more.

Your light or dark theme choice is stored in your own browser (local storage) so the site remembers it. It never leaves your device.

ratio uses Vercel Web Analytics to count page views and see which pages are useful. It sets no cookies and stores no personal identifiers: visitors are counted with a hash of the request that is discarded within a day, so we can't identify you or follow you across sites.

We see aggregate figures only, such as page views, referring sites, country and device type.

We also count a few anonymous events to learn which recommendations help: when a recommendation is shown (the preset car if you picked one, the tyre size, how and where you drive, and the recommended category and tyre), when you open a tyre, and when you click through to a retailer (which tyre, its rank, the page and the car and size it was for). None of it is tied to you.

ratio is hosted on Vercel. Like any web host, Vercel processes standard request information such as IP address and browser type to deliver pages and protect against abuse. See Vercel's privacy policy for details.

Some tyre recommendations link to retailers such as Tyroola. These links pass through ratio (addresses starting /go/) and then on to the retailer. Once you arrive, the retailer and any referral network it uses may set their own cookies, including cookies that record that you came from ratio. Their privacy policies apply from that point.

Retailer links carry a short code naming the page, car, size and rank they came from, so a referral network can report which pages led to a sale. It contains nothing about you.

Where a link is a referral link, ratio may earn a commission if you buy, at no extra cost to you. This never changes which tyres ratio recommends or the order they appear in, and referral links are labelled next to where they appear.

If what ratio collects changes, this page will be updated before it happens.