Standard license plate screws are 1/4 inch diameter with a 20 threads-per-inch pitch, typically sold as 1/4"-20 bolts

The screws that hold your license plate to your vehicle are not random fasteners. Most states and the federal standard call for 1/4"-20 bolts — that is, 1/4 inch in diameter with 20 threads per inch. The length is usually 3/4 inch to 1 inch, depending on whether you are mounting directly to the bumper or using a bracket. If you are replacing a lost or stripped screw, buying the wrong size will either not fit the existing hole or strip it further.

The reason this matters: license plate mounting holes are drilled to a specific size at the factory. A screw that is too small will spin freely and fall out. A screw that is too large will not thread into the hole or will crack the plastic frame. Getting the size right the first time saves you a trip back to the hardware store and keeps your plate from rattling loose on the road.

Key Takeaways

  • Standard license plate screws are 1/4"-20 bolts, 3/4 to 1 inch long, and available at any hardware store or auto parts retailer.
  • Stainless steel screws resist rust and corrosion better than zinc-plated ones, especially in coastal areas or climates with road salt.
  • If your existing screw is stripped or missing, bring the plate to the hardware store to test-fit before buying a full set.
  • Some states allow or require tamper-resistant screws with a special head shape; check your state's DMV rules before replacing them.

Where to buy the right screws

Hardware stores, auto parts chains, and online retailers all stock 1/4"-20 bolts in the lengths you need. Home Depot, Lowe's, Ace Hardware, AutoZone, O'Reilly, and NAPA all carry them. A box of stainless steel 1/4"-20 bolts typically costs between $5 and $15 depending on the quantity and material. Stainless steel is worth the small premium because it resists rust far better than zinc-plated steel, especially if you live where road salt is used in winter.

If you are unsure whether you need 3/4 inch or 1 inch length, bring your license plate or the old screw with you. A hardware store employee can hold it up to the bolt display and confirm the fit. Buying a small quantity first — say, four or five bolts — lets you test one before committing to a full box.

Stainless steel versus zinc-plated

The two most common finishes are stainless steel and zinc-plated steel. Stainless steel does not rust and will look clean for years, even in wet or salty conditions. Zinc-plated steel is cheaper but will eventually show rust spots, especially in coastal areas or places where road salt is spread in winter. If you plan to keep the vehicle for more than a few years, stainless steel is the better choice.

Some hardware stores also sell brass or nylon screws, but these are not recommended for license plates. Brass is softer and can strip easily. Nylon is not strong enough to hold a plate securely, especially on a vehicle that vibrates at highway speeds.

Tamper-resistant screws and state rules

A growing number of states require or allow tamper-resistant license plate screws — bolts with a special head shape (often a pin in the center) that cannot be removed with a standard screwdriver or wrench. These are designed to prevent theft of plates or the vehicle itself. States including California, New York, Texas, and others have adopted them or made them optional.

Before replacing your screws, check your state's DMV website or call your local registration office to see whether tamper-resistant screws are required, recommended, or prohibited. If your state requires them and you install standard screws, you may be cited during a traffic stop. If your state allows them but does not require them, using them is optional and adds a small layer of security.

How to remove and replace stripped or missing screws

If a screw is stripped — meaning it spins but does not tighten — you have two options. The first is to use the next size up: a 5/16"-18 bolt will fit into a stripped 1/4"-20 hole if you drill it out slightly, but this damages the plate and is not ideal. The better option is to use a threaded insert or helicoil, a small coiled sleeve that you install in the stripped hole to restore the original thread size. A hardware store can show you how, or a mechanic can do it in minutes for $10 to $20.

If a screw is straightforward missing, measure the remaining screws or bring the plate in to confirm the size, then buy a replacement in the same finish. Install it hand-tight first, then use a wrench to snug it down — do not over-tighten, as this can crack the plastic frame or strip the bolt.

Tools you need

You need only two tools to install license plate screws: a wrench or socket that fits the bolt head (usually 3/8 inch or 7/16 inch for a 1/4"-20 bolt) and a screwdriver or hex key to hold the bolt steady on the back side of the plate if your plate has a frame. Some people use a power drill with a socket attachment, but hand tools are safer and less likely to over-tighten and strip the bolt.

If you are installing tamper-resistant screws, you will also need the special tool or key that comes with them. Do not lose this tool — you will need it if you ever have to remove the plate again.

Frequently Asked Questions

Can I use any bolt as long as it fits the hole?

No. The hole is threaded for a 1/4"-20 bolt specifically. A bolt that is close in size but not exact will either not thread in or will strip the hole. Always confirm the size before buying.

What if I lost the tool for my tamper-resistant screws?

Contact your state's DMV or the screw manufacturer to request a replacement tool. Some manufacturers will mail one free if you provide proof of purchase. Keep the tool in your glove box or with your vehicle documents.

Do I need to replace all four screws at once?

No. You can replace one or two at a time. However, if you are switching from standard to tamper-resistant screws, replace all four so they match and so you have only one tool to keep track of.

Will a longer screw damage my bumper?

Yes, if it is too long. A screw longer than 1 inch can poke through the back of the bumper or frame and cause damage. Stick to 3/4 inch to 1 inch depending on your plate thickness and mounting setup.

Can I use a bolt with a different thread pitch, like 1/4"-28?

No. The hole is drilled and tapped for 1/4"-20 specifically. A 1/4"-28 bolt will not thread in properly and may strip the hole. Always use 1/4"-20.