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Enter a tire size and instantly see all the dimensions. Enter a second size and compare them: rolling circumference, outer diameter, sidewall height, ground clearance, and the speedometer reading change.

The tire calculator is the app for the website reifenrechner.org. It performs all calculations on your device – no account, no registration, and no internet connection required.

WHAT FOR

• Look up a tire size without comparing it to anything
• Buy new wheels and want to know if the size fits

• Drive winter tires in a different size than summer tires
• Check if the rolling circumference remains within the usual tolerance range of -2.5% to +1.5%
• Know how much the speedometer reads fast or slow after a tire change

Recalculate the mileage after changing tire sizes

Find a suitable alternative size for your existing rim

SCALE DRAWING

Each result is illustrated: the wheel from the side and the tire from the front. For two sizes, both wheels are shown side-by-side, to scale. Whether the new tire is taller, wider, or lower profile is revealed in half a second – the millimeters are displayed below.

WHAT THE CALCULATOR PROVIDES

Outer diameter, rolling circumference – unloaded and under load – tire width, sidewall height, rim diameter, and ground clearance, each with the old value next to it and the difference in millimeters or percent. It also displays the actual speed at the speedometer reading and the actual mileage.

If the load rating and speed index are printed on the sidewall, the app compares these as well and indicates if the new tire has a lower load capacity or is rated for a lower speed – this is the only instance where a lower value is not just a difference, but a defect.

RIM, OFFSET, AND SPACER

If you know the rim dimensions, you also get the change in track width, the distance to the fender, and the distance to the strut. All three fields are optional; without them, the app only calculates the tire sizes.

ALTERNATIVE TIRE SIZES

Enter a size and receive all sizes whose rolling circumference falls within the selected tolerance – sorted by tolerance, commercially available sizes are marked, optionally only for the same rim size.

ALL COMMON STYLES

205/55 R16 · 205/55R16 · 205 55 16 · P225/50R17 · 195 R 14 (the 82 series is added) · 31x10.50 R15 · 190/65 R 390. Designations such as 91V, XL, RF, C, M+S, 3PMSF, or RunFlat are not a problem. Suggestions as you type show the common sizes with their outer diameter.

HISTORY

The last 50 calculations are retained, searchable, and can be tapped to continue calculating. They are stored exclusively on the device and are not transferred anywhere.

LIGHT AND DARK

The app starts in light mode. Tapping the title bar switches to light mode, and the choice will apply the next time you launch the app. You can also select "Same as device" in the menu.

WITHOUT INTERNET

All tables are stored within the app. It performs the same calculations without an internet connection. A connection is only required for displaying the ads.

IMPORTANT NOTICE

All information is provided for guidance only and does not constitute approval. Whether a tire size is permitted on a vehicle is solely determined by the vehicle registration documents – either the vehicle registration certificate (Part I) or the Certificate of Conformity (CoC). This app is an independent tool, is not affiliated with any government agency, tire manufacturer, or testing organization, and does not replace an inspection by a qualified mechanic.

Privacy Policy: https://reifenrechner.org/datenschutz-app