What socket size are lug nuts?
There isn't a universal lug-nut socket size. Most passenger cars use sockets between roughly 17 mm and 23 mm across flats, with 19 mm and 21–22 mm being particularly common. The exact size depends on the vehicle and wheel design, so verify for your model.
Common lug nut socket sizes you may encounter
The hex size of lug nuts—the size of the socket you turn with a wrench or impact tool—varies by manufacturer and model. Below are the sizes you’re most likely to encounter on everyday vehicles, listed in both metric and approximate imperial equivalents.
- 19 mm across flats — the most common size for many modern passenger cars and light trucks.
- 21 mm across flats — used on a number of European and Asian makes and some mid-size SUVs.
- 22 mm across flats — found on various European brands and some pickups.
- 23 mm across flats — used on a minority of models; verify for your vehicle.
- 13/16 inch across flats (about 20.6 mm) — common alternative for some American cars and older fleets.
- 7/8 inch across flats (about 22.2 mm) — seen on some trucks and larger SUVs.
- 1 inch across flats (25.4 mm) — rare for standard passenger cars; may appear on certain heavy-duty or aftermarket lug nuts.
Note: Some vehicles use special lug-nut configurations such as 12-point nuts or wheel-hose designs that may require different sockets or impact tools. Always check your vehicle’s documentation or physically verify the correct size by fitting sockets with care to avoid rounding the nut.
How to determine the exact lug nut socket size for your vehicle
To avoid damage and ensure proper torque, identify the correct socket size using a methodical approach. The steps below help you confirm the exact size for your vehicle.
- Check the owner’s manual, door jamb sticker, or wheel and tire information placard for lug-nut size or torque specs.
- Inspect the lug nuts or wheel-nut packaging, or consult the vehicle manufacturer's service information online if available.
- Measure the lug nut across flats with calipers or a precise ruler to identify the closest standard size (in metric or inches).
- If you’re unsure, start with the nearest size and verify fitment carefully: it should slide on smoothly, seat evenly, and not require hammering. If it binds, switch to the next size and re-check.
Once you have the correct size, use a properly fitting socket (preferably 6-point for better grip) and apply torque with a calibrated torque wrench to the manufacturer’s specifications.
Safety and best practices
Follow standard safety practices: park on a level surface, apply the parking brake, use wheel chocks, and tighten in a star pattern. Re-torque after installation, when the wheel is on the ground and the vehicle is at normal operating weight.
Summary
There is no single universal lug-nut socket size. The most common across-flats sizes you’ll encounter are 19 mm, 21–22 mm, and 23 mm (or their imperial equivalents 13/16" to 7/8"), but exact sizes vary by vehicle and wheel design. Always verify with official documentation or by measuring, and use the correct torque specification to ensure a safe wheel installation.
What size are standard lug nuts?
The three most common hex sizes for lug nuts are 17 mm, 19 mm, and 21 mm, while 22 mm, 23 mm, 11⁄16 inch (17.5 mm), and 13⁄16 inch (20.6 mm) are less commonly used.
Is 13/16 the same as 21mm?
No, 13/1613 / 1613/16 inch is not the same as $21$mm, but they are very close and often used interchangeably.13/1613 / 1613/16 inch is equal to $20.65$mm, while $21$mm is equal to approximately 0.830.830.83 inches, meaning $21$mm is slightly larger. Because the sizes are so close, a $21$mm socket or wrench will often fit a 13/1613 / 1613/16 inch nut or bolt, and vice versa, though there can be a less-than-perfect fit depending on the manufacturing tolerances of the tools and fasteners.
- 13/1613 / 1613/16 inch = $20.65$mm
- $21$mm = 0.826770.826770.82677 inches, which is slightly larger than 13/1613 / 1613/16 inch
What size socket is needed for lug nuts?
The socket size for lug nuts varies by vehicle, but the most common sizes are 17 mm, 19 mm, and 21 mm. To find the correct size for your car, check the owner's manual, a sticker on the driver's side door jamb, or take one of the lug nuts to an auto parts store for measurement. It is best to use a six-point socket and a quality one to avoid damaging the lug nut.
Common socket sizes
- Metric: 17 mm, 19 mm, 21 mm
- Imperial: 3/4 inch (often fits 19 mm) and 13/16 inch (often fits 21 mm)
How to find the right size
- Check your vehicle's documentation: The owner's manual or a placard inside the driver's side door jamb will list the correct size.
- Take a lug nut to a professional: An auto parts store or a mechanic can measure it for you.
Tips for choosing the right socket
- Use a six-point socket: These are less likely to strip the lug nuts than a 12-point socket.
- Use a thin-wall socket: If you're working with wheels that have narrow clearance around the lug nuts, a thin-wall socket is necessary.
- Use impact sockets for impact wrenches: If you are using an impact wrench, use an impact-rated socket to prevent the socket from breaking under high torque.
- Consider a half-size socket set: If your lug nuts are swollen, rusted, or damaged, a half-size socket set may be necessary to get them off.
What size wrench do I need to remove lug nuts?
1/2-inch
For most passenger cars and light trucks, a 1/2-inch drive impact wrench is typically the best choice for loosening and tightening lug nuts. This site provides the right balance of power and maneuverability for most everyday tasks.
