About us

Editorial Policy

Last updated: 10 November 2026.

How the tools are built

Every calculator on TyreCalc implements a published, checkable formula: tyre diameter from width, aspect ratio and rim diameter; circumference and revolutions per mile from diameter; fuel cost from distance, MPG and pump price; speedometer error from the ratio of two diameters. There is no hidden model and no guesswork — the same inputs always give the same outputs, and the formula is explained on the tool page or in the linked guide.

How numbers are checked

Tyre dimensions are nominal industry figures: a size marked 205/55R16 is defined by its width, aspect ratio and rim diameter, and the calculated diameter follows from those three numbers. Real tyres vary slightly by manufacturer and tread design, which is why every dimensional result is labelled an estimate. Fuel and cost figures use the prices and consumption figures the user enters — we never invent a pump price or an MPG figure for a vehicle. Where a guide states a typical figure (for example a typical tread life), it is labelled typical and the range is given.

Safety first, always

A wrong tyre size can cause accidents, so fitment content carries the strongest warning on the site: calculations are not safety approvals, the door-jamb placard is authoritative, load index and speed rating must match or exceed the original, and a tyre professional must make the fitment decision. No article or tool will ever tell a reader that a size “fits” their car — only that its diameter is within a stated percentage of the original. See the full Disclaimer.

Money and affiliate links

TyreCalc is supported by advertising and affiliate links. Those links never change a calculation or a recommendation, and advertisers do not review or approve content. See our Affiliate Disclosure.

Corrections

If a calculation or a guide is wrong, we fix it and note the correction. Report errors via the contact page with the page address and the numbers you entered.