What size socket is a lug nut?

In short: there isn’t a universal lug-nut socket size. The correct size depends on your vehicle’s wheel lug nuts. Most modern passenger cars use metric hex sizes of 17, 19, or 21 millimeters; some older or heavier vehicles use imperial sizes such as 13/16 inch or 3/4 inch.

Common lug nut hex sizes you’ll encounter

The following sizes cover the majority of cars, SUVs, and light trucks you’ll service at home or in a shop. Use this as a reference when you don’t have the exact spec handy.

• 17 mm


• 19 mm


• 21 mm


• 13/16 in (about 20.6 mm)


• 3/4 in (about 19.0 mm)

Note: These are typical sizes you’ll see, but the exact lug-nut size for your vehicle may differ. Always verify against official documentation or measure directly on the lug nut.

How to determine the correct size

If you don’t have the owner’s manual handy, follow these steps to identify the right socket size without damaging the lug nuts or wheels.

1. Check the owner’s manual or a repair guide for the exact lug-nut size specified for your vehicle model and trim level.


2. Inspect the lug nuts on the wheel: look for any size markings, or compare the flats visually with a set of calibration gauges or a ruler if you have none handy.


3. When in doubt, bring the wheel or the vehicle to a shop and have a technician confirm the size using proper gauges.


4. Once you identify a likely size, test it carefully: it should fit snugly with no wobble or rounding. Do not force a larger or smaller socket onto the nut.


5. If your vehicle uses locking lug nuts, locate the special key. If the key is missing, contact the dealership or a qualified shop for access or replacement options.

After you determine the correct size, remember to use the proper torque specification from the manufacturer and tighten in a crisscross or star pattern to ensure even seating of the wheel.

Extra considerations: torque, locks, and safety

Socket size is just one part of wheel maintenance. Proper torque, lock-nut management, and safe handling are equally important to prevent wheel detachments and other hazards.

• Torque specs vary by vehicle but are commonly in the 80–100 ft-lbs range for many passenger cars, with higher values for trucks and SUVs. Always follow the manufacturer’s specification.


• Use a calibrated torque wrench and tighten in a star pattern to evenly cinch the wheel onto the hub.


• Be mindful of locking lug nuts. Keep the key in a secure place and have a backup plan if it’s lost or damaged.


• Avoid using incorrect or heavily worn sockets, which can strip the lug nut flats and create safety risks.

Summary

There is no single universal lug-nut socket size. The right size depends on your vehicle, with common metric sizes being 17, 19, and 21 mm and some imperial equivalents such as 13/16 in. When in doubt, consult the owner’s manual, measure the lug nut flats, or have a professional confirm the correct size. Always torque wheels to the manufacturer’s specification and handle locking lug nuts with care to maintain wheel security and safety.

Is a 7/8 wrench the same as 22mm?

A: 22mm = 0.866", which essentialy is a 7/8" socket. A 7/8" socket will work on a 22mm lug nut, but it can feel a little loose. The other way around, a 22mm can work on a 7/8" lug nut, but it can be really snug, which is not bad.

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.

What size is a standard lug nut?

There is no single "standard" lug nut size; sizes vary by vehicle, but common metric thread sizes are 12mm×1.2512 m m cross 1.2512𝑚𝑚×1.25 and 12mm×1.5012 m m cross 1.5012𝑚𝑚×1.50, while common SAE sizes are 1/2′′−201 / 2 double prime minus 201/2′′−20 and 9/16′′−189 / 16 double prime minus 189/16′′−18. The socket size needed to fit a lug nut also varies, with 17mm,19mm,17 m m comma 19 m m comma17𝑚𝑚,19𝑚𝑚, and 21mm21 m m21𝑚𝑚 being the most common hex sizes for the wrench or socket. 
Common lug nut sizes 

• Thread size: The thread size is measured by the diameter of the wheel stud. 
  • Metric: Common sizes include 10mm,12mm,10 m m comma 12 m m comma10𝑚𝑚,12𝑚𝑚, and 14mm14 m m14𝑚𝑚. For example, a lug nut might be specified as 12mm×1.5012 m m cross 1.5012𝑚𝑚×1.50, where 12mm12 m m12𝑚𝑚 is the diameter and 1.501.501.50 is the thread pitch (the distance between threads). 
  • SAE: Common sizes include 7/16′′,1/2′′,9/16′′,7 / 16 double prime comma 1 / 2 double prime comma 9 / 16 double prime comma7/16′′,1/2′′,9/16′′, and 5/8′′5 / 8 double prime5/8′′. For example, 1/2′′−201 / 2 double prime minus 201/2′′−20 means the diameter is 1/21 / 21/2 inch and there are 202020 threads per inch. 
• Hex size: The hex size is the measurement across the flats of the lug nut, which determines the size of the socket you need. 
  • Most common: 17mm,19mm,17 m m comma 19 m m comma17𝑚𝑚,19𝑚𝑚, and 21mm21 m m21𝑚𝑚. 
  • Less common: 22mm,23mm,22 m m comma 23 m m comma22𝑚𝑚,23𝑚𝑚, and some SAE sizes like 11/16′′11 / 16 double prime11/16′′ (17.5mm17.5 m m17.5𝑚𝑚) and 13/16′′13 / 16 double prime13/16′′ (20.6mm20.6 m m20.6𝑚𝑚). 

How to find the right size

1. Consult your owner's manual: The most reliable way to determine the correct lug nut and socket size for your vehicle is to check the owner's manual. 
2. Measure the stud: If you cannot find the information in your manual, use dial or digital calipers to precisely measure the diameter and thread pitch of the wheel stud. 
3. Check the socket: Alternatively, try a common size like 17mm,19mm,17 m m comma 19 m m comma17𝑚𝑚,19𝑚𝑚, or 21mm21 m m21𝑚𝑚 to see which one fits snugly without being too loose or too tight.