Terms of Service
Effective date: June 2026
Use of the service
TreadSize is provided free of charge for personal and professional informational use. You may use the calculators, guides, and reference pages for any lawful purpose.
No warranty
TreadSize provides tire size calculations based on standard ETRTO formulas. We make no warranty — express or implied — that the computed values are suitable for any specific vehicle, application, or jurisdiction. Tire fitment involves physical constraints (wheel well clearance, load rating, speed rating, offset, hub bore) that our tools do not assess.
Always confirm fitment with a qualified tire professional and your vehicle's owner's manual before purchasing or installing tires.
Limitation of liability
TreadSize and its operators shall not be liable for any damages arising from use of the information on this site, including but not limited to tire-fitment decisions, vehicle damage, or personal injury.
Affiliate links
When affiliate links are live (disclosed at the point of use), clicking them may result in us earning a commission if you make a purchase. This does not affect the calculations shown.
Contact
Questions: hello@treadsize.com
Sources and calculation limits
Source note updated
June 2026
Calculation scope
Nominal dimensions from the size markings supplied. Vehicle installation is not verified.
Method and inputs
- Nominal geometry calculated from tire-size markings
- Original-equipment size references supplied by users or vehicle placards
- Diameter differences and theoretical rotation ratios; no installation approval
Calculated dimensions do not verify the tire model, load or speed rating, approved rim width, wheel offset, physical clearance, or vehicle systems. Confirm those against manufacturer specifications before installation.