235/45R18 tire size: 26.33 in tall
Diameter, sidewall, width and revs per mile for 235/45R18, the common sizes within 3% of its diameter, and what each one does to the speedometer.
235/45R18, in short: 26.33 in (669 mm) tall and 235 mm (9.25 in) wide, with a 4.16 in (105.8 mm) sidewall, for a 18-inch wheel. Circumference is 82.71 in, so it turns about 766 times per mile (calculated from the nominal size).
Calculated from the size: sidewall = 235 × 45% = 105.75 mm; diameter = 2 × 4.163 in + 18 in; revs per mile = 63,360 ÷ (π × diameter).
Sizes within 3% of 235/45R18
22 common sizes come within ±3% of 26.33 in: 6 on the same 18-inch wheel, 4 plus-size and 12 minus-size. The last column is what the speedometer shows when the vehicle, set up for 235/45R18, is doing a true 60 mph.
| Size | Fit | Diameter | Difference | Width | Sidewall | Revs/mile (calc.) | Speedometer at a true 60 |
|---|---|---|---|---|---|---|---|
| 235/45R18 | This size | 26.33 in | - | 235 mm | 4.16 in | 766 | 60.0 mph |
| 205/60R16 | Minus 2 | 25.69 in | -2.44% | 205 mm | 4.84 in | 785 | 61.5 mph |
| 225/55R16 | Minus 2 | 25.74 in | -2.21% | 225 mm | 4.87 in | 783 | 61.4 mph |
| 215/60R16 | Minus 2 | 26.16 in | -0.64% | 215 mm | 5.08 in | 771 | 60.4 mph |
| 205/65R16 | Minus 2 | 26.49 in | +0.63% | 205 mm | 5.25 in | 761 | 59.6 mph |
| 225/60R16 | Minus 2 | 26.63 in | +1.15% | 225 mm | 5.31 in | 757 | 59.3 mph |
| 215/65R16 | Minus 2 | 27.00 in | +2.57% | 215 mm | 5.50 in | 747 | 58.5 mph |
| 245/45R17 | Minus 1 | 25.68 in | -2.45% | 245 mm | 4.34 in | 785 | 61.5 mph |
| 225/50R17 | Minus 1 | 25.86 in | -1.78% | 225 mm | 4.43 in | 780 | 61.1 mph |
| 205/55R17 | Minus 1 | 25.88 in | -1.70% | 205 mm | 4.44 in | 779 | 61.0 mph |
| 235/50R17 | Minus 1 | 26.25 in | -0.28% | 235 mm | 4.63 in | 768 | 60.2 mph |
| 215/55R17 | Minus 1 | 26.31 in | -0.06% | 215 mm | 4.66 in | 767 | 60.0 mph |
| 225/55R17 | Minus 1 | 26.74 in | +1.59% | 225 mm | 4.87 in | 754 | 59.1 mph |
| 215/45R18 | Same wheel | 25.62 in | -2.69% | 215 mm | 3.81 in | 787 | 61.7 mph |
| 245/40R18 | Same wheel | 25.72 in | -2.32% | 245 mm | 3.86 in | 784 | 61.4 mph |
| 225/45R18 | Same wheel | 25.97 in | -1.35% | 225 mm | 3.99 in | 777 | 60.8 mph |
| 215/50R18 | Same wheel | 26.46 in | +0.52% | 215 mm | 4.23 in | 762 | 59.7 mph |
| 245/45R18 | Same wheel | 26.68 in | +1.35% | 245 mm | 4.34 in | 756 | 59.2 mph |
| 225/50R18 | Same wheel | 26.86 in | +2.02% | 225 mm | 4.43 in | 751 | 58.8 mph |
| 225/40R19 | Plus 1 | 26.09 in | -0.91% | 225 mm | 3.54 in | 773 | 60.6 mph |
| 235/40R19 | Plus 1 | 26.40 in | +0.28% | 235 mm | 3.70 in | 764 | 59.8 mph |
| 245/40R19 | Plus 1 | 26.72 in | +1.48% | 245 mm | 3.86 in | 755 | 59.1 mph |
| 255/40R19 | Plus 1 | 27.03 in | +2.68% | 255 mm | 4.02 in | 746 | 58.4 mph |
A taller tire makes the speedometer read low, a shorter one high. Plus-sizing keeps the diameter close by trading sidewall for wheel. Any replacement needs a load index at least as high as the vehicle's tire placard calls for, and a wheel width the tire is approved for.
235/45R18 compared
235/45R18 side by side with 235/40R19 and 225/45R18: dimension by dimension, and what the swap does to the speedometer.
235/45R18 vs 235/40R19
+0.28% diameter| 235/45R18 | 235/40R19 | Difference | |
|---|---|---|---|
| Overall diameter | 26.33 in | 26.40 in | +0.07 in (+0.3%) |
| Section width | 235 mm | 235 mm | +0 mm |
| Sidewall height | 4.16 in | 3.70 in | -0.46 in |
| Wheel diameter | 18 in | 19 in | +1 in |
| Circumference | 82.7 in | 82.9 in | +0.2 in |
| Revs per mile (calc.) | 766 | 764 | -2 |
235/40R19 is 0.3% taller than 235/45R18. At a true 60 mph the speedometer shows 59.8 mph (it reads low), and when it shows 60 you're doing 60.2 mph.
235/45R18 vs 225/45R18
-1.35% diameter| 235/45R18 | 225/45R18 | Difference | |
|---|---|---|---|
| Overall diameter | 26.33 in | 25.97 in | -0.35 in (-1.3%) |
| Section width | 235 mm | 225 mm | -10 mm |
| Sidewall height | 4.16 in | 3.99 in | -0.18 in |
| Wheel diameter | 18 in | 18 in | +0 in |
| Circumference | 82.7 in | 81.6 in | -1.1 in |
| Revs per mile (calc.) | 766 | 777 | +10 |
225/45R18 is 1.3% shorter than 235/45R18. At a true 60 mph the speedometer shows 60.8 mph (it reads high), and when it shows 60 you're doing 59.2 mph.
Which vehicles come with 235/45R18
Vehicles sold in the US that have 235/45R18 as the standard size on these trims, with the page that lists it. The tire placard on the driver's door edge or post has the size, and the load and inflation, for the exact vehicle.
- Toyota Camry 2025 model year · SE, XLE (2024 gas and hybrid; 2025 hybrid-only lineup)Mavis Tire OE fitment page, 2025 Toyota Camry Hybrid SE (size flagged standard 'S')
- Tesla Model 3 2025 model year · Long Range (18-in. standard; 19-in. optional)Mavis Tire OE fitment page, 2025 Tesla Model 3 Long Range (size flagged standard 'S')
Vehicles mostly picked from Carscoops: 2025 U.S. car sales, full-year top 25 (Car and Driver data, January 2026).
Questions about 235/45R18 tires
How tall is a 235/45R18 tire?
What is 235/45R18 in inches?
How many revolutions per mile does a 235/45R18 tire make?
What size can replace 235/45R18?
235/45R18 vs 235/40R19: what's the difference?
Which vehicles come with 235/45R18 tires?
How these numbers are worked out
- NHTSA: Tire safety, everything rides on it (reading the sidewall and the placard)
- Tire Rack: How do I calculate tire dimensions?
- Jalopnik: What the 3% rule means for your tires (April 2026)
Checked October 2026. Dimensions are nominal, calculated from the size designation. A real tire's diameter, width and revs per mile vary by brand, tread depth, rim width and load, so check the maker's spec sheet.
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