265/40R18 tire size
265/40R18 is a metric size: 26.3" tall, 10.4" wide, on a 18" rim — about a 26.5x10.50R18. The sidewall is 4.2" and the tire turns 765 times per mile.
265/40R18 specs
| Overall diameter (height) | 26.35" · 669 mm |
|---|---|
| Section width | 10.43" · 265 mm |
| Sidewall height | 4.17" · 106 mm (40% of width) |
| Rim diameter | 18" |
| Circumference | 82.77" · 2.102 m |
| Revolutions per mile | 765 (476 per km) |
| Inch (flotation) equivalent | 26.5x10.50R18 |
Equivalent sizes on a 18" rim
Sizes within ±5% of the overall diameter. Green rows are inside the usual ±3% limit for keeping the speedometer, ABS and gearing right; red rows are bigger changes that need clearance checks.
| Size | Diameter | Difference | Width | Speedo at 60 | |
|---|---|---|---|---|---|
| 225/45R18 common | 25.97" | -1.42% | -40 mm | 59.1 mph | compare → |
| 245/40R18 common | 25.72" | -2.39% | -20 mm | 58.6 mph | compare → |
| 225/40R18 common | 25.09" | -4.78% | -40 mm | 57.1 mph | compare → |
| 245/45R18 common | 26.68" | +1.27% | -20 mm | 60.8 mph | compare → |
| 235/50R18 common | 27.25" | +3.44% | -30 mm | 62.1 mph | compare → |
| 235/45R18 common | 26.33" | -0.07% | -30 mm | 60.0 mph | compare → |
| 235/40R18 common | 25.40" | -3.59% | -30 mm | 57.8 mph | compare → |
| 225/50R18 common | 26.86" | +1.94% | -40 mm | 61.2 mph | compare → |
| 255/40R18 common | 26.03" | -1.20% | -10 mm | 59.3 mph | compare → |
| 245/50R18 common | 27.65" | +4.93% | -20 mm | 63.0 mph | compare → |
| 275/35R18 common | 25.58" | -2.91% | +10 mm | 58.3 mph | compare → |
| 265/35R18 common | 25.30" | -3.96% | 0 mm | 57.6 mph | compare → |
| 255/45R18 common | 27.04" | +2.62% | -10 mm | 61.6 mph | compare → |
| 215/55R18 common | 27.31" | +3.66% | -50 mm | 62.2 mph | compare → |
| 275/40R18 common | 26.66" | +1.20% | +10 mm | 60.7 mph | compare → |
| 215/45R18 common | 25.62" | -2.76% | -50 mm | 58.3 mph | compare → |
| 285/35R18 | 25.85" | -1.87% | +20 mm | 58.9 mph | compare → |
| 315/30R18 | 25.44" | -3.44% | +50 mm | 57.9 mph | compare → |
| 295/35R18 | 26.13" | -0.82% | +30 mm | 59.5 mph | compare → |
| 335/30R18 | 25.91" | -1.64% | +70 mm | 59.0 mph | compare → |
| 215/50R18 | 26.46" | +0.45% | -50 mm | 60.3 mph | compare → |
| 295/40R18 | 27.29" | +3.59% | +30 mm | 62.2 mph | compare → |
| 265/45R18 | 27.39" | +3.96% | 0 mm | 62.4 mph | compare → |
| 285/40R18 | 26.98" | +2.39% | +20 mm | 61.4 mph | calculate → |
| 305/35R18 | 26.41" | +0.22% | +40 mm | 60.1 mph | calculate → |
| 345/35R18 | 27.51" | +4.41% | +80 mm | 62.6 mph | calculate → |
| 305/40R18 | 27.61" | +4.78% | +40 mm | 62.9 mph | calculate → |
| 155/70R18 | 26.54" | +0.75% | -110 mm | 60.4 mph | calculate → |
| 26x12.00R18 | 26.00" | -1.32% | +40 mm | 59.2 mph | calculate → |
| 26x6.00R18 | 26.00" | -1.32% | -113 mm | 59.2 mph | calculate → |
| 26x8.00R18 | 26.00" | -1.32% | -62 mm | 59.2 mph | calculate → |
| 145/70R18 | 25.99" | -1.34% | -120 mm | 59.2 mph | calculate → |
| 325/35R18 | 26.96" | +2.32% | +60 mm | 61.4 mph | calculate → |
| 165/70R18 | 27.09" | +2.84% | -100 mm | 61.7 mph | calculate → |
| 145/80R18 | 27.13" | +2.99% | -120 mm | 61.8 mph | calculate → |
| 155/60R18 | 25.32" | -3.89% | -110 mm | 57.7 mph | calculate → |
| 305/30R18 | 25.20" | -4.33% | +40 mm | 57.4 mph | calculate → |
| 345/30R18 | 26.15" | -0.75% | +80 mm | 59.6 mph | calculate → |
| 315/35R18 | 26.68" | +1.27% | +50 mm | 60.8 mph | calculate → |
| 195/60R18 | 27.21" | +3.29% | -70 mm | 62.0 mph | calculate → |
| 205/45R18 | 25.26" | -4.11% | -60 mm | 57.5 mph | calculate → |
Plus / minus sizing: 17" and 19" rims
Same overall height on a different rim. Check wheel width and clearance before switching.
| Size | Diameter | Difference | Width | Speedo at 60 | |
|---|---|---|---|---|---|
| 215/55R17 common | 26.31" | -0.13% | -50 mm | 59.9 mph | compare → |
| 235/40R19 common | 26.40" | +0.21% | -30 mm | 60.1 mph | compare → |
| 275/35R19 common | 26.58" | +0.88% | +10 mm | 60.5 mph | compare → |
| 225/40R19 common | 26.09" | -0.99% | -40 mm | 59.4 mph | compare → |
| 235/50R17 common | 26.25" | -0.36% | -30 mm | 59.8 mph | compare → |
| 265/35R19 common | 26.30" | -0.16% | 0 mm | 59.9 mph | compare → |
| 305/30R19 | 26.20" | -0.54% | +40 mm | 59.7 mph | compare → |
| 315/30R19 | 26.44" | +0.36% | +50 mm | 60.2 mph | compare → |
| 335/35R17 | 26.23" | -0.43% | +70 mm | 59.7 mph | calculate → |
| 195/60R17 | 26.21" | -0.51% | -70 mm | 59.7 mph | calculate → |
| 145/80R17 | 26.13" | -0.81% | -120 mm | 59.5 mph | calculate → |
| 295/40R17 | 26.29" | -0.21% | +30 mm | 59.9 mph | calculate → |
| 165/70R17 | 26.09" | -0.96% | -100 mm | 59.4 mph | calculate → |
Try another size against 265/40R18
Questions
What size is 265/40R18 in inches?
265/40R18 is about 26.3" tall and 10.4" wide on a 18-inch rim — roughly a 26.5x10.50R18 in inch sizing.
What does 265/40R18 mean?
265 mm section width, sidewall 40% of the width (4.17"), radial construction, 18-inch rim.
What tire sizes are equivalent to 265/40R18?
On the same 18" rim, within 3% of the diameter: 235/45R18 (-0.07%), 305/35R18 (+0.22%), 215/50R18 (+0.45%), 345/30R18 (-0.75%), 155/70R18 (+0.75%), 295/35R18 (-0.82%).
How many revolutions per mile does a 265/40R18 tire make?
About 765 revolutions per mile (circumference 82.8").
How these numbers are computed
Diameter = rim + 2 × sidewall, sidewall = width × aspect ÷ 100, circumference = π × diameter, revolutions per mile = 63,360 ÷ circumference. Real tires differ by brand by a few tenths of an inch. Last reviewed October 14, 2026.