Tire Tread Depth Chart: Limits, Legal Minimums and Replacement Guide

Safe tire tread depth is 4/32″ (3.2 mm) or more: AAA recommends replacing tires at 4/32″, while 2/32″ (1.6 mm) is the legal minimum in most U.S. states. New tires typically start at 10/32″ to 12/32″. The charts below show what every depth from 12/32″ to 2/32″ means in 32nds and millimeters, the legal minimums for cars and trucks, and the depths to replace at for rain, snow, and off-road driving.

How to Read a Tire Tread Depth Chart

A tire tread depth chart matches a measured depth, in 32nds of an inch or millimeters, to one of three conditions:

• Optimal / New Tires: full grip and braking performance
• Caution / Near Limit: reduced traction in rain or snow
• Critical / Replace Immediately: at or below the legal minimum

For example, tires at 4/32″ are still legal but already lose grip in rain. Measure first with our step-by-step guide on how to check your tire tread depth, then read your result in the charts below.

Tire Tread Depth Chart: 2/32 to 12/32 (32nds and mm)

Find your measured depth in the first column to see its millimeter value and what it means for your tires:

NeoTires Safety Note: measure several spots across each tire (center, inner, and outer edges), because tires often wear unevenly and a single reading can mislead. The 4/32″ replacement point is AAA's recommendation; 2/32″ is the legal minimum in most states.

Is 8/32, 6/32 or 4/32 Tread Good?

Tread above 4/32″ is good, 4/32″ is AAA's point to replace, and 2/32″ is the legal limit. Here is what the most-measured depths mean:

Is 8/32 Tread Good?

Yes. 8/32″ (6.3 mm) is good tread: the tire has worn only a few 32nds from new and still grips well in rain and snow. Keep checking it monthly.

Is 6/32 Tread Good?

Yes. 6/32″ (4.8 mm) is safe and above AAA's 4/32″ replacement point. Measure again before winter, because the tire is two 32nds from the depth where wet and snow traction drop.

Is 4/32 Tread Safe?

4/32″ (3.2 mm) is legal but it is the point to replace. AAA recommends replacing tires at 4/32″, and its testing found that tires worn to 4/32″ needed an average of 87 feet more to stop on wet pavement from 60 mph than new tires.

Is 3/32 Tread Safe?

No, not on wet or slushy roads. 3/32″ (2.4 mm) is above the 2/32″ legal minimum, but the grooves channel little water, so the hydroplaning risk is high. Replace the tires soon.

Tread Depth Conversion: mm to 32nds

1/32″ equals 0.79 mm. To convert, multiply 32nds by 0.79 to get millimeters, or divide millimeters by 0.79 to get 32nds. For example, 4/32″ is 3.2 mm, and 10 mm is about 12.6/32″.

Tread Depth of New Tires: What to Expect from Fresh Tires

New tires typically have 10/32″ to 12/32″ of tread, depending on type: all-season tires about 10/32″ to 11/32″, winter tires 11/32″ to 12/32″, performance and summer tires a shallower 8/32″ to 10/32″, and off-road truck tires 12/32″ to 19/32″ or more. These are typical ranges; the exact new depth of a model is in its specifications.

All-Season Tires (≈10–11/32″ / 7.9–8.7 mm)

This is the typical new depth for passenger car, sedan, and crossover tires. It balances wet and dry traction: grooves deep enough for rain, but not so deep that dry handling suffers.

Winter / Snow Tires (≈11–12/32″ / 8.7–9.5 mm)

Deeper tread lets snow pack into the grooves, which increases grip on snow. These tires wear faster in warm weather, so their starting depth matters for winter performance.

Performance / Summer Tires (≈8–10/32″ / 6.3–7.9 mm)

Performance and summer tires start shallower than all-season tires for road contact, cornering precision, and response on dry roads. Because they start with less depth, they reach the 4/32″ replacement point sooner, so check them more often.

Truck / Off-Road Tires (≈12–19/32″ / 9.5–15.1 mm)

Extra tread handles mud, gravel, and heavy loads, and the deeper grooves extend tire life on rough terrain.

Legal Minimum Tread Depth by State and Vehicle

The legal minimum tread depth for car tires is 2/32″ (1.6 mm) in most U.S. states. California sets 1/32″ in any two adjacent grooves for most tires, under Vehicle Code §27465. Trucks and buses must have at least 4/32″ on the front tires and 2/32″ on all other tires under federal rule 49 CFR 393.75. Check your state's law, and remember that the legal minimum is not the safe depth: AAA recommends replacing at 4/32″.

Recommended Depths for Different Driving Conditions

Replace tires at 4/32″ for rain and snow, and keep more tread for off-road and heavy-load use. The sections below explain each condition:

Snow and Winter Driving

Snow traction drops as tread wears: Consumer Reports testing found tires worn to 4/32″ notably worse in snow, so replace winter-driving tires no later than 4/32″ and check them before the season starts. Deep grooves let snow pack into the tread, and snow-on-snow contact grips better than rubber alone; as the grooves get shallower, that packing effect fades and the tires slide more easily on packed snow.

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Off-Road and Heavy Load Conditions

Off-road and heavy-load driving call for more tread than the 4/32″ road minimum. Deeper tread gives two things:

• the bite to grip loose surfaces such as gravel, mud, and dirt
• a larger rubber reserve for the faster wear that rough terrain and extra weight cause

Driving off-road on shallow tread reduces traction and raises the risk of punctures and sidewall damage.

Rain and Wet Roads

You need at least 4/32″ of tread for safe wet-weather driving. Below that, the grooves can't channel water away fast enough, and the tire rides on the water instead of the road, which is hydroplaning.

The effect on stopping distance is large. Consumer Reports testing found that tires worn to 4/32″ need an additional 30 feet to stop on wet pavement compared with new tires. In AAA's testing at 60 mph, tires worn to 4/32″ needed an average of 87 feet more to stop on wet pavement, a 43% increase.

Tread depth chart for wet conditions

DOT Tread Depth for Trucks and Commercial Vehicles

Federal rules require at least 4/32″ on the front (steer) tires of buses, trucks, and truck tractors, and at least 2/32″ on all other tires, including drive and trailer tires (49 CFR 393.75). Steer tires need the deeper tread because they control the vehicle's direction. Depth is measured in a major tread groove, not on tie bars or humps.

Important Note: these are federal minimums for commercial vehicles, not replacement targets. Follow your fleet guidelines or ask a commercial tire specialist for replacement points that fit your loads and routes.

Tread Depth Summary: When Tires Need Replacing

Replace tires when the tread depth reaches the limits below, or when their age or condition calls for it, whichever comes first.

Based on the Tread Depth

At 2/32″ or below, replacement is mandatory: the tires are legally worn out in most states. At 3/32″, they are unsafe on wet and slushy roads; replace them soon. At 4/32″, AAA's replacement point, grip in rain and snow drops; replace them. Above 4/32″, you're safe; keep checking monthly.

Based on Age and Condition

Replace tires that show bulges, cracks, or severe wear, whatever their tread depth. Uneven wear points to a mechanical problem, such as alignment or inflation, that needs fixing. Also replace tires that are more than 6 years old, even if tread remains.

Are Your Tires Running Out of Tread? NeoTires Can Help

If the charts show your tires are low on tread, replace them. At NeoTires, you'll find tires for every vehicle, season, and budget: orders are dispatched the same day and delivered in 2–3 business days across the U.S., and tires labeled Free Shipping ship free. Use our tool to Search Tires By Size, or chat with us for advice. Drive safely and check your tread depth regularly!

References:

AAA (American Automobile Association) | Tread Lightly: Worn Tires Put Drivers at Risk

AAA | Tread Confidently

California Vehicle Code | Section 27465

U.S. Department of Transportation | 49 CFR 393.75: Tires