Tire size
33x12.50R18 in metric
A 33x12.50R18 tire is 33.0 inches (838 mm) tall and 12.5 inches (318 mm) wide, on a 18-inch wheel. Its sidewall is 60% of its width. The closest metric sizes on a 18-inch wheel are 295/65R18, 275/70R18, 325/60R18, 265/70R18.
| 33x12.50R18 | Inches | Metric |
|---|---|---|
| Overall diameter (height) | 33.0 in | 838 mm |
| Section width | 12.5 in | 318 mm |
| Sidewall height | 7.5 in | 190 mm |
| Wheel (rim) diameter | 18 in | 457 mm |
| Circumference | 103.7 in | 2633 mm |
| Revolutions | 611 per mile | 380 per km |
How it's worked out
Inch sizes give the height first: 33x12.50R18 is 33.0 in tall and 12.5 in wide for a 18 in wheel, so each sidewall is (33.0 - 18) / 2 = 7.5 in.
Similar sizes
Sizes within about 3.5% of the height of 33x12.50R18. The last column is your real speed at an indicated 60 mph if your speedometer was set for 33x12.50R18.
| Size | Height | vs 33x12.50R18 | Real speed at 60 mph shown |
|---|---|---|---|
| 33x10.50R15 | 33.0 in | +0.0% | 60.0 mph |
| 33x12.50R15 | 33.0 in | +0.0% | 60.0 mph |
| 33x12.50R17 | 33.0 in | +0.0% | 60.0 mph |
| 33x12.50R20 | 33.0 in | +0.0% | 60.0 mph |
| 275/60R20 | 33.0 in | -0.0% | 60.0 mph |
| 255/80R17 | 33.1 in | +0.2% | 60.1 mph |
| 255/85R16 | 33.1 in | +0.2% | 60.1 mph |
| 295/65R18 | 33.1 in | +0.3% | 60.2 mph |
Going bigger from 33x12.50R18
If 33x12.50R18 is your stock size, these are the commonly sold axle ratios that come closest to your stock overall gearing on bigger tires.
| Your ratio now | On 35s | On 37s |
|---|---|---|
| 3.21 | 3.42 exact 3.40 | 3.55 exact 3.60 |
| 3.42 | 3.55 exact 3.63 | 3.91 exact 3.83 |
| 3.55 | 3.73 exact 3.77 | 3.91 exact 3.98 |
| 3.73 | 3.91 exact 3.96 | 4.10 exact 4.18 |
| 3.91 | 4.10 exact 4.15 | 4.30 exact 4.38 |
| 4.10 | 4.30 exact 4.35 | 4.56 exact 4.60 |
Exact = your ratio x new height / 33.0. Front and rear axles must match on a 4WD. Not every ratio is made for every axle. Want more pull than stock? Go one step shorter. More in the regearing guide.
Questions
What is 33x12.50R18 in metric?
838 mm tall and 318 mm wide on a 18-inch wheel. The nearest common metric sizes are 295/65R18, 275/70R18, 325/60R18, 265/70R18.
How tall is a 33x12.50R18 tire?
33.0 inches on paper. Many inch-sized tires measure slightly under their label once mounted, so check the maker's spec sheet if it matters.
How many revolutions per mile does 33x12.50R18 do?
About 611 per mile (380 per km).
Nominal dimensions, calculated from the size marking. Real tires differ slightly by brand, rim width, pressure and wear. Fitment depends on your vehicle, lift and wheels: this page doesn't say whether a size fits. Updated 2026-11-14.