Car magnet sizes and specs: 12 x 18, 12 x 24, 24 x 36, and why 30 mil magnet matters
A car magnet is a printed sign on flexible magnetic sheeting that sticks to a steel door panel. The two specs that matter are size (it has to fit the flat part of the door) and thickness (30 mil is the vehicle-grade standard). Measure the flat area between body lines and trim before you pick a size.
Car magnet size chart
| Size | Centimeters | Fits | Typical use |
|---|---|---|---|
| 12 x 18 in | 30 x 46 cm | Most car and small SUV doors | Logo, business name, phone |
| 12 x 24 in | 30 x 61 cm | Most sedans, SUVs, and pickups | The most popular door magnet |
| 18 x 24 in | 46 x 61 cm | Larger SUV and pickup doors | More lines, a service list |
| 24 x 36 in | 61 x 91 cm | Work trucks, cargo vans, box trucks | Fleet branding readable at a distance |
| Bumper-size, about 3 x 11.5 in | 8 x 29 cm | Tailgates, trunk lids | Website or slogan strip |
Material specs
| Spec | Vehicle grade | Why it matters |
|---|---|---|
| Thickness | 30 mil (0.030 in, 0.76 mm) | Holds at highway speeds; 15 to 20 mil is for indoor and refrigerator magnets |
| Corners | Rounded, about 1/2 to 1 in radius | Square corners give wind a place to start peeling |
| Weight | Roughly half a pound per square foot at 30 mil | A 12 x 24 in magnet weighs about a pound |
| UV-resistant ink, ideally with a laminate | Resists fading from sun and car washes |
Lettering that reads from the road
Signage designers use roughly 1 inch of letter height per 10 feet of viewing distance. On a 12 x 24 inch magnet, a business name about 3 inches tall and a phone number about 2 inches tall can be read from a car length or more away. Keep it to a logo, the business name, one service line, and a phone number or website; a magnet read at a stoplight has about three seconds.
Will a car magnet stick to my vehicle?
Only to steel. Magnets do not stick to aluminum, fiberglass, carbon fiber, or plastic panels, and some recent trucks and SUVs have aluminum doors, hoods, or tailgates. Check with a fridge magnet before ordering. The magnet also needs a flat area; it should not bridge a deep body line, molding, or door handle.
Care rules
- Remove the magnet and wipe both the magnet and the door at least once a week, so moisture and grit do not get trapped.
- Do not apply to freshly painted panels; let new paint cure for at least a couple of months first.
- Remove before automatic car washes.
- Store flat, never rolled tightly or folded, and out of direct heat.
What we recommend
Order matched pairs (driver and passenger doors) at 12 x 24 inches on 30 mil magnet with rounded corners, and repeat your logo and colors from your staff badges and banners so the brand looks consistent. If you would like NameBadge.com to quote vehicle magnets alongside banners, signs, and name badges for your team, request a quote. We are a family-owned US manufacturer operating since 2008, and US orders over $200 ship free.
Frequently asked questions
What is the standard size for a car door magnet?
12 x 24 inches (30 x 61 cm) is the most common, with 12 x 18 inches for smaller doors. Measure the flat area of your door first.
How thick should a car magnet be?
30 mil (0.030 inch, 0.76 mm). It is the vehicle-grade standard; thinner magnet is made for refrigerators and indoor use.
Can car magnets fly off on the highway?
A clean, flat, 30 mil magnet with rounded corners in full contact with a steel panel stays put at highway speeds. Trapped dirt, curved surfaces, and square corners are what cause magnets to lift.
Do car magnets damage paint?
Not when they are removed and cleaned weekly. Leaving one on for months can trap moisture and leave an outline from uneven fading, and new paint should be allowed to cure first.
Why will my car magnet not stick?
The panel is probably aluminum, fiberglass, or plastic, which magnets cannot grip. Test the spot with any household magnet.
Like our answers?
Make NameBadge your preferred source on Google
One tap puts a preferred badge on our answers in your Google Search & AI results. No account, no sign-up.