Penny and Quarter Tread Depth Tests

Tread depth is measured in 32nds of an inch. New passenger tires usually start around 10/32" to 11/32".

Penny test (2/32")

Put a Lincoln penny head-first into a tread groove. If you can see the top of Lincoln's head, the tread is at or below about 2/32", and it's time to replace the tire. Many U.S. states use 2/32" as the legal minimum.

Quarter test (4/32")

Put a quarter head-first into a groove. If you can see the top of Washington's head, you have about 4/32" or less. Consumer Reports recommends replacing tires at 4/32", because wet and snow traction drop sharply as tread wears.

Tread wear indicator bars

Tires have small raised bars molded across the bottom of the grooves at 2/32". When the tread is flush with these bars, the tire is worn out (NHTSA).

Tips

• Check several grooves on the inner, center and outer parts of each tire. Uneven wear can point to alignment or pressure problems.
• A tread depth gauge costs a few dollars and is more precise than a coin.

Related guides

• When to Replace Your Tires
• Tire Rotation and Pressure Basics
• All-Season vs Winter Tires

General information only, not a substitute for an in-person inspection by a qualified tire professional. If in doubt, have your tires checked.

Sources

• NHTSA – TireWise / Tire Safety brochure (DOT HS 811 151)
• NHTSA – Tires
• Consumer Reports – Tire buying guide
• U.S. Tire Manufacturers Association – Tire Care

Last updated October 28, 2026.