A tire tread depth calculator estimates remaining safe mileage and replacement urgency based on your current and original tread depth. Enter measurements in 32nds of an inch or millimeters — the standard used by tire manufacturers and technicians worldwide.
Tire Measurements
Measure with a tread gauge or use the penny/quarter test
Replacement Status
Remaining Safe Miles
estimated
Wear Used
of usable tread
Tread Analysis
Tread Remaining
Enter your tire measurements and click Calculate Tread Life to see your remaining safe mileage.
How to Use the Tire Tread Depth Calculator
The tire tread depth calculator estimates how many safe miles remain on your tires and whether you should replace them now, monitor them closely, or continue driving normally. Regular tread checks prevent dangerous blowouts and reduced wet-weather grip.
Step 1: Measure Your Tread Depth
Use a tread depth gauge (available at auto parts stores for $5-10) for an accurate reading. Quick checks: insert a US quarter into the tread groove — if you can see the top of Washington's head, you have less than 4/32" remaining (replace soon). Use a penny for the legal minimum: if Lincoln's head is fully visible, you're at or below 2/32" (replace immediately).
Step 2: Select Original Tread Depth
Most standard passenger car tires start with 10/32"-11/32" (about 8-9mm) of new tread. Check your tire's sidewall or manufacturer specs if unsure. SUV and truck tires typically start at 14/32"-18/32". Selecting the right original depth makes the wear rate calculation accurate.
Step 3: Enter Miles Driven
Enter the total miles you've driven on these specific tires. This lets the calculator determine your personal wear rate in 32nds per thousand miles, giving a more accurate remaining life estimate than generic averages alone.
Understanding Replacement Urgency Levels
The calculator assigns one of four urgency levels: Safe (above 4/32") — continue normal monitoring; Monitor (4/32") — wet weather grip is reduced, plan replacement soon; Replace Soon (3/32") — approaching legal limit, replace within the next 2,000 miles; Replace Now (2/32" or below) — legally unsafe in most states, replace immediately.
FAQ
What is the minimum safe tire tread depth?
The legal minimum in most US states is 2/32 inch (1.6mm). However, safety experts recommend replacing tires at 4/32 inch (3.2mm) — especially for wet-weather driving. At 4/32, stopping distances in rain increase significantly. Winter driving conditions require even more tread; consider replacing winter tires at 6/32 inch.
How do I measure tire tread depth?
Use a tread depth gauge (available at auto parts stores for $5-10) for precise measurements. A quick check: insert a US quarter upside down into the tread groove. If you can see the top of Washington's head, you have less than 4/32 inch remaining. Use a penny for the 2/32 minimum — if Lincoln's entire head is visible, replace immediately.
How many miles does tire tread last?
Most tires start with 10/32 to 11/32 inch of tread and are rated for 40,000-70,000 miles depending on tire type and driving conditions. Tread wears at roughly 1/32 inch per 10,000 miles under normal conditions, though aggressive driving, under-inflation, and misalignment accelerate wear significantly.
Is this tool free?
Yes, completely free with no signup required. All calculations run in your browser.
Is my data safe?
Yes. Everything runs locally in your browser. No information is transmitted or stored.
What does 32nds of an inch mean for tire tread?
Tire tread depth in the US is measured in 32nds of an inch. New tires typically have 10/32 to 11/32 inch (about 8-9mm) of tread. The legal minimum is 2/32 inch (1.6mm), which equals about 0.0625 inches. To convert: multiply mm by 0.1248 to get approximate 32nds, or use this calculator's metric/imperial toggle.