Tread Depth Calculator & UTQG Treadwear Rating Explainer FREE
Tread depth calculator quick reference: new tires = 10/32", replace at 4/32", legal minimum 2/32". Plus understand UTQG treadwear ratings (200, 400, 600) and tire longevity.
The Treadwear rating, part of the UTQG (Uniform Tire Quality Grade) system, is a comparative number indicating a tire's expected wear life relative to a standard reference tire rated at 100. A higher number generally suggests a longer potential lifespan, but actual mileage can vary significantly based on driving habits, road conditions, climate, and tire care. This tool helps you understand what a specific treadwear number implies.
A tire's tread depth determines its safety — not just the treadwear rating. Use these benchmarks to evaluate any tire.
| Tread Depth | mm | Status | Action |
|---|---|---|---|
| 10/32" | 7.9mm | New tire | Full service life ahead |
| 6/32" | 4.8mm | Good | Normal wear — monitor regularly |
| 4/32" | 3.2mm | Plan replacement | Wet performance degrading — replace soon |
| 2/32" | 1.6mm | Legal minimum | Replace immediately — fails inspection below this |
Tip: Use a tread depth gauge ($5–$10) for accurate measurement. Check all four tires and measure at multiple points across each tire width.
- Locate the Treadwear rating on your tire's sidewall. It's a number usually following the word 'TREADWEAR'.
- Enter this number (e.g., 200, 400, 600) into the 'Treadwear Rating' field.
- Click 'Explain Rating' or the explanation will update automatically if you have already submitted once and the input is valid.
- The results will provide a general explanation and specific commentary on the entered treadwear value.
How do I measure tread depth without a gauge?
Use the penny test or quarter test. Penny test: insert a penny head-first into a tread groove. If you can see all of Lincoln's head, tread is at or below 2/32" — replace immediately. Quarter test: if you can see the top of Washington's head, tread is at or below 4/32" — consider replacing soon.
What is the minimum legal tread depth?
In the United States, the legal minimum tread depth is 2/32 of an inch (1.6mm). Most states will fail a vehicle inspection below this. However, safety experts recommend replacing tires at 4/32" (3.2mm) because wet stopping distance increases significantly between 4/32" and 2/32".
How much tread depth does a new tire have?
Most new passenger car tires have between 9/32" and 11/32" of tread depth (7–8.7mm). All-season tires typically start at 10/32", performance tires may start at 8/32", and truck/SUV tires often start at 11/32" or more.
At what tread depth should I replace my tires?
Replace at 4/32" (3.2mm) for year-round safety, especially if you drive in rain or snow. At this depth, wet braking distances increase noticeably. Don't wait until 2/32" — that's the legal minimum, not the safe minimum.
All tools and information provided on TireCalculatorHub are for informational purposes only. Treadwear ratings are comparative and actual tire life depends on many factors. Consult with tire professionals for specific advice.
TireCalculatorHub is not liable for any damages or issues arising from the use of information or tools on this website.