What size is a lug nut socket?
The lug nut socket size is not universal; it depends on the lug nuts used by your vehicle. The most common hex sizes you’ll encounter are 17–22 mm in metric or 13/16" and 3/4" in imperial, with typical socket drives of 1/2" or 3/8" for standard tools and heavier-duty setups using 3/4".
Common metric lug nut sizes
Many cars and light trucks use metric measurements. Having a few standard metric sockets on hand covers the majority of models.
- 17 mm
- 19 mm
- 21 mm
- 22 mm
In practice, these sizes fit a large portion of modern passenger vehicles. If your wheel uses one of these metrics, select the matching size for proper seating on the nut.
Common imperial lug nut sizes
Some older cars, trucks, and certain imports use inch-based hex sizes. The two most common options are:
- 13/16 inch
- 3/4 inch
These imperial sizes fit many trucks and some older passenger vehicles. Always verify, as there are exceptions and some models use uncommon sizes.
How to determine your lug nut size
Because lug nuts and wheels vary by model, identify the correct size using multiple methods before selecting a socket.
- Consult the vehicle’s owner’s manual or the wheel information placard for lug nut size or torque specs.
- Inspect a lug nut or wheel stud for any size stamping, if present.
- Measure across the flats of a lug nut with calipers or a ruler to determine the hex size.
- Bring the wheel or lug nut to an auto parts store to match a socket, or try several sizes with care to avoid rounding the nut.
Notes: Lug nuts come in different seat styles (conical, ball) and the socket must match the seat type. Use a 6-point socket for most lug nuts unless your hardware specifies otherwise. Also, choose the drive size that matches your tool (typically 1/2" drive for hand tools and many impact wrenches; some setups use 3/8" or 3/4").
Socket type and drive
Socket size refers to the hex dimension, while drive refers to the square peg that fits your ratchet or impact wrench. For most cars, a 1/2" drive socket is standard; heavy-duty applications may use 3/4" drive. Always use impact-rated sockets if you’re using an impact wrench, and ensure the socket matches the lug nut’s seat type and the tool’s drive size.
Tips for safe tire service
Torque the lug nuts to the manufacturer’s specification, tighten in a star pattern, and recheck torque after a short drive. If you’re unsure of your size, seek assistance from a professional or visit an automotive parts retailer for guidance.
Summary
Lug nut socket sizes vary by vehicle. The most common ranges are 17–22 mm (metric) and 13/16"–3/4" (imperial). Always verify using your owner’s manual, the wheel placard, or by measuring the hex on the lug nut, and ensure you use the correct drive and seat type. Carrying a small set that includes these sizes will cover the vast majority of passenger cars and light trucks.
