Standard license plate screws are 1/4 inch diameter, typically 3/4 to 1 inch long
Most U.S. states use 1/4-20 stainless steel screws to mount license plates. The "1/4" refers to the diameter, and "20" means 20 threads per inch. Length varies slightly by state and mounting style, but 3/4 inch and 1 inch are the most common. Stainless steel resists rust and corrosion from road salt and weather, which is why it's the standard choice.
Your state's Department of Motor Vehicles may specify the exact screw size in their vehicle registration materials, or you can check your vehicle's manual. If you're replacing screws that came with your plate, measure the old ones or bring them to a hardware store to match. Most hardware stores stock these screws in the fastener aisle, usually labeled as "license plate screws" or in the general stainless steel bolt section.
Some states allow or require plastic covers over the screws for aesthetic reasons. These covers fit over standard 1/4-inch screws and don't change the underlying fastener size. If your plate came with covers, keep them — they're often state-specific and part of your registration setup.
Key Takeaways
- Standard license plate screws are 1/4-20 stainless steel, typically 3/4 to 1 inch long, and available at any hardware store.
- Your state's DMV materials or your vehicle manual may specify the exact length required for your registration.
- Stainless steel is essential because it resists rust from road salt and weather exposure.
- If your plate came with plastic screw covers, those fit over standard 1/4-inch screws and should be kept as part of your registration.
- Measure old screws or bring them to a hardware store to confirm the size before purchasing replacements.
Why stainless steel matters for outdoor mounting
License plates spend their entire life exposed to weather, road salt, moisture, and temperature swings. Regular steel screws rust quickly under these conditions, and rust can damage the plate itself and make future removal difficult. Stainless steel doesn't rust in the same way because it contains chromium, which forms a protective layer on the metal surface.
Galvanized screws (steel coated with zinc) are cheaper and sometimes used, but they corrode faster than stainless steel, especially in areas with heavy road salt use. If you live near the ocean or in a region where roads are salted in winter, stainless steel is worth the small extra cost. The screws typically cost $3 to $8 for a pack of four at a hardware store.
How to measure if you're unsure of the size
If you have the old screws, the easiest method is to take them to a hardware store and ask staff to match them. They can measure the diameter and thread count in seconds. If you don't have the old screws, you can measure the hole in your license plate with a ruler or caliper — the hole diameter tells you the screw size you need.
Another option is to call your state's DMV directly and ask what screw size they recommend for your plate type. Some states print this information on the registration paperwork that came with your plate. If you're buying screws for a new plate, the plate itself often comes with the correct screws already attached, so you only need replacements if they're lost or damaged.
Installation tips to avoid stripping or over-tightening
Hand-tighten the screws first to make sure they thread smoothly into the mounting holes. If you feel resistance or grinding, stop — the hole may be stripped or the screw may be the wrong size. Once hand-tight, use a screwdriver (Phillips or slotted, depending on the screw head) to tighten firmly but not forcefully. Over-tightening can strip the threads in the plate or the mounting bracket, making future removal harder.
Stainless steel screws are softer than steel, so they strip more easily if you use excessive force. Tighten until snug, then stop. The plate should not move or rattle, but you should still be able to remove the screw with normal hand pressure on the screwdriver. If the screw spins without tightening, the hole is stripped and you may need a slightly larger screw or a threaded insert to repair it.
Where to buy replacement screws
Hardware stores like Home Depot, Lowe's, and Ace Hardware stock 1/4-20 stainless steel screws in the fastener section. They're usually sold in small packs of 4, 8, or 10. Online retailers like Amazon and eBay also carry them, often in bulk packs if you need extras. Local independent hardware stores can usually match your old screws on the spot and may have smaller quantities available.
Auto parts stores (AutoZone, O'Reilly, NAPA) sometimes carry license plate screws, though their selection is smaller than a general hardware store. If you're in a hurry, a hardware store is usually faster because they have the screws in stock and staff can verify the size when ready. Expect to pay $3 to $10 for a small pack, depending on the retailer and whether you buy stainless steel or galvanized.
What to do if the mounting holes are stripped
If the holes in your plate or mounting bracket are stripped and screws won't tighten, you have a few options. The simplest is to move to a different hole if your plate has extras — most plates have four holes but only require two for mounting. If all holes are stripped, you can use a slightly larger screw (5/16 inch instead of 1/4 inch), though this is not ideal and may not fit all mounting brackets.
A better solution is a threaded insert, a small metal sleeve that screws into the stripped hole and provides new threads for your original screw size. Hardware stores sell these in kits for about $5 to $10. Installation requires a drill and the correct insert size, so this is more involved than straightforward replacing screws. If you're not comfortable drilling, a mechanic or hardware store staff can often do it for you for a small fee.
Frequently Asked Questions
Can I use any stainless steel screw, or does it have to say "license plate screw"?
Any 1/4-20 stainless steel screw of the correct length works. "License plate screw" is just a marketing label. What matters is the diameter (1/4 inch), thread count (20 threads per inch), material (stainless steel), and length (usually 3/4 or 1 inch). Verify these specs and you're good to go.
What if my state requires a specific screw type or color?
Some states specify chrome-plated, painted, or covered screws for appearance. Check your registration paperwork or contact your DMV to confirm. If your plate came with screws, use the same type as replacements. If you're unsure, a hardware store can show you options and help you match what you need.
Do I need to remove my license plate to replace the screws?
Not necessarily. If you can access the screws from the front with a screwdriver, you can replace them in place. If the mounting bracket is on the back of the plate and difficult to reach, removing the plate makes the job easier. Either way, the process takes just a few minutes once you have the right screws.
Will using the wrong size screw damage my plate?
A screw that's too large may crack the plate or strip the holes. A screw that's too small won't hold the plate securely and may fall out. Stick with 1/4-20 stainless steel in the correct length for your state, and you won't have problems. When in doubt, ask a hardware store staff member to verify the size.