Metric tire size

215/45R18 tire size

A 215/45R18 tire is 25.6 inches (651 mm) tall and 8.5 in wide, for a 18-inch wheel, with a 3.8 in sidewall. That is the nominal size worked out from the code. Makers publish 25.4–25.9 in for real 215/45R18 tires (5 makers).

Diameter25.6 in651 mm

Width8.5 in215 mm

Sidewall3.8 in97 mm

Revs per mile787nominal, published 803–817

Wheel width7–8 inapproved by every listing

Compare 215/45R18 with other sizes

Set up for: comparing 215/45R18 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 215/45R18 tires: published diameters

Figures from the makers' own data books. They differ from the 25.6 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	25.6–25.9 in	803–811	7–8 in	3
Goodyear	25.6 in	815	7–8 in	1
Hankook	25.4–25.6 in	812–817	7–8 in	4
Toyo	25.6 in	811	—	1
Uniroyal	25.6 in	812	7–8 in	1

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 215/45R18. Same diameter is only one part of fitting a different size.

Wheel	Real sizes within 3% (closest first)
15-inch	205/65R15 (25.5 in, −0.5%), 265/50R15 (25.4 in, −0.7%), 275/50R15 (25.8 in, +0.8%)
16-inch	245/50R16 (25.6 in, +0.1%), 205/60R16 (25.7 in, +0.3%), 225/55R16 (25.7 in, +0.5%)
17-inch	275/40R17 (25.7 in, +0.2%), 245/45R17 (25.7 in, +0.2%), 315/35R17 (25.7 in, +0.2%)
18-inch	275/35R18 (25.6 in, −0.2%), 195/50R18 (25.7 in, +0.2%), 245/40R18 (25.7 in, +0.4%)
20-inch	285/25R20 (25.6 in, ±0.0%), 235/30R20 (25.6 in, −0.3%), 245/30R20 (25.8 in, +0.7%)

Popular comparisons with 215/45R18

215/45R18 vs 205/60R16+0.3% diameter 215/45R18 vs 225/40R18−2.1% diameter

FAQ

How tall is a 215/45R18 tire?

25.6 inches (651 mm) calculated from the size code. Makers publish 25.4–25.9 in for real tires in this size; the difference comes from tread design and construction.

How do you work out the 215/45R18 diameter?

Sidewall = 215 mm × 45% = 96.8 mm. Diameter = 18 in wheel + 2 × 96.8 mm ÷ 25.4 = 25.62 in.

Is 215/45R18 a 26-inch tire?

It is about 25.6 in tall nominally, so it is close to 26 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 215/45R18?

Real sizes within 3% of its diameter include 245/50R16 (+0.1%), 275/40R17 (+0.2%) and 285/25R20 (±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 215/45R18 make?

About 787 calculated from its unloaded diameter. Makers publish 803–817 revs per mile, measured under load (a loaded tire rolls on a slightly smaller radius), which is why published figures are higher.

Open 215/45R18 in the converter · Tire size chart

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.