Measure Tread Depth
Learn how to collect tread depth readings by groove and position.
Read the guide
Tire Tread Depth Converter
Convert tread depth between 32nds of an inch and millimeters.
Convert tread depth units
Frequently asked questions
What does 32nds mean in tire tread depth?
In the United States, tread depth is commonly measured in 32nds of an inch.
How many millimeters is 2/32 inch?
Two thirty-seconds of an inch is approximately 1.59 mm, commonly rounded to 1.6 mm.
Is tread depth alone enough to decide if a tire is safe?
No. Tire condition also depends on age, damage, weather cracking, uneven wear, inflation, load, and applicable local requirements.
Does this converter provide legal advice?
No. This converter is informational only. Check local requirements and consult qualified tire or service professionals.
Reference note
This converter uses the standard relationship of 1 inch = 25.4 mm. Results are rounded for general reference. Tire tread measurements should be made with a proper tread depth gauge.
Related Tread Depth Resources
Average Measurements
Average multiple tread depth values before using them in wear-rate calculations.
Open averaging toolWear Rate Calculator
Use converted tread depth values in the reference-only wear-rate calculator.
Open wear calculator