Flotation tire size

33x12.50R18 in metric

A 33x12.50R18 is a flotation size: 33.0 inches tall and 12.5 in wide, for a 18-inch wheel (838 × 318 mm). The closest metric sizes on the same 18-inch wheel are 295/65R18 (33.1 in), 275/70R18 (33.2 in) and 325/60R18 (33.4 in). Makers publish 32.5–33 in for real 33x12.50R18 tires (5 makers).

Diameter33.0 in838 mm

Width12.5 in318 mm

Sidewall7.5 in190 mm

Revs per mile611nominal, published 630–643

Wheel width8.5–11 inapproved by every listing

Compare 33x12.50R18 with other sizes

Set up for: comparing 33x12.50R18 with a size you're considering · Different situation?

Your current size

Current tire size

e.g. 265/70R17, 2657017 or 33x12.50R20

Where do I find my size?

It's on the tire sidewall, e.g. P265/70R17 115T, and on the tire placard sticker on the driver's door jamb (also in the owner's manual). The placard shows the size the vehicle came with; the sidewall shows what is fitted now. If they differ, use the placard as your starting point. Digits are enough here: 2657017 or 33125020.

Size you're considering

Size you're considering (2)

Real 33x12.50R18 tires: published diameters

Figures from the makers' own data books. They differ from the 33.0 in calculated figure because each tread design and construction measures slightly differently.

Maker (data book)	Published diameter	Revs per mile	Approved wheel width	Listings
Falken	32.8 in	642	8.5–11 in	1
Goodyear	32.8 in	634	8.5–11 in	1
Hankook	32.5–32.7 in	643	8.5–11 in	2
Nitto	32.76–32.95 in	—	8.5–11 in	2
Toyo	32.5–33 in	630–639	8.5–11 in	3

Sources: maker data books (PDF), checked 2026-11-05. Brand names identify the data source only.

Equivalent sizes on other wheels

Sizes that appear in the maker data books with a diameter within 3% of 33x12.50R18. Same diameter is only one part of fitting a different size.

Wheel	Real sizes within 3% (closest first)
15-inch	33x10.50R15 (33.0 in, ±0.0%), 33x12.50R15 (33.0 in, ±0.0%), 33x13.50R15 (33.0 in, ±0.0%)
16-inch	255/85R16 (33.1 in, +0.2%), 285/75R16 (32.8 in, −0.5%), 305/70R16 (32.8 in, −0.6%)
17-inch	255/80R17 (33.1 in, +0.2%), 295/70R17 (33.3 in, +0.8%), 235/85R17 (32.7 in, −0.8%)
18-inch	295/65R18 (33.1 in, +0.3%), 275/70R18 (33.2 in, +0.5%), 325/60R18 (33.4 in, +1.1%)
20-inch	275/60R20 (33.0 in, ±0.0%), 325/50R20 (32.8 in, −0.6%), 305/55R20 (33.2 in, +0.6%)
22-inch	315/45R22 (33.2 in, +0.5%), 275/50R22 (32.8 in, −0.5%), 355/40R22 (33.2 in, +0.5%)

Popular comparisons with 33x12.50R18

275/70R18 vs 33x12.50R18−0.5% diameter 275/65R18 vs 33x12.50R18+2.9% diameter 285/65R18 vs 33x12.50R18+1.3% diameter 285/70R18 vs 33x12.50R18−2.1% diameter 295/70R18 vs 33x12.50R18−3.7% diameter

FAQ

How tall is a 33x12.50R18 tire?

33.0 inches (838 mm) calculated from the size code. Makers publish 32.5–33 in for real tires in this size; the difference comes from tread design and construction.

Is 33x12.50R18 a 33-inch tire?

It is about 33.0 in tall nominally, so it is close to 33 inches. Real tires in a size vary slightly by model; check the maker's spec sheet for the exact tire.

What sizes are equivalent to 33x12.50R18?

Real sizes within 3% of its diameter include 255/85R16 (+0.2%), 33x11.50R17 (±0.0%) and 33x11.50R20 (±0.0%). Equal diameter alone doesn't make a size suitable: wheel width, offset, clearance and load rating all matter.

How many revolutions per mile does a 33x12.50R18 make?

About 611 calculated from its unloaded diameter. Makers publish 630–643 revs per mile, measured under load (a loaded tire rolls on a slightly smaller radius), which is why published figures are higher.

Open 33x12.50R18 in the converter · Tire size chart · 33-inch tires

Important: These are calculated (nominal) dimensions, not a fitment recommendation. Real tires of the same size differ by brand and model (makers allow about ±3% of section height), and width changes with the rim it is mounted on. The math can't see wheel width and offset, clearance at full steering lock and suspension travel, load index, speed rating, or what your vehicle maker approves. Before changing size, check your door-jamb placard and owner's manual and ask a tire professional. A replacement tire must meet or exceed the load index and speed rating on the placard.