225/40R18 Tire Size Specifications & Compatible Vehicles
Overall Diameter
637.2 mm
Section Width
225 mm
Sidewall Height
90.0 mm
Circumference
2001.8 mm
Revs/Mile
804
Rim Diameter
18"
Inch Equivalent
25.1x8.9R18
Rim Width (ETRTO)
6.5" – 8.5"
Compatible Vehicles
The following vehicles use 225/40R18 tires from the factory:
Alternative Tire Sizes
These tire sizes are within 3% overall diameter of 225/40R18 and may be used as replacements:
Popular Comparisons
See how 225/40R18 compares to other common tire sizes:
225/45R17 vs 225/40R18 Sport sedan plus-one upgrade 225/40R18 vs 235/40R18 Performance tire width upgrade 225/40R18 vs 245/35R19 Performance plus-one upgrade 225/40R18 vs 245/40R18 Width upgrade on 18-inch 205/45R17 vs 225/40R18 Hot hatch plus-one upgrade 215/45R18 vs 225/40R18 Wider lower profile swap
Understanding 225/40R18
The tire size 225/40R18 means the tire has a section width of 225mm, an aspect ratio of 40% (the sidewall height is 40% of the width), and fits a 18-inch rim.
Sidewall Height = 225 x 0.4 = 90.0 mm
Overall Diameter = (90.0 x 2) + (18 x 25.4) = 637.2 mm
Circumference = 637.2 x π = 2001.8 mm
Overall Diameter = (90.0 x 2) + (18 x 25.4) = 637.2 mm
Circumference = 637.2 x π = 2001.8 mm
Frequently Asked Questions
The 225/40R18 tire size is used on 6 vehicle trims including the 2025 Toyota Corolla, 2024 Toyota Corolla, 2023 Toyota Corolla and 3 more.
A 225/40R18 tire has an overall diameter of 637.2mm (25.1 inches). The sidewall height is 90.0mm, and the total circumference is 2002mm.
For 225/40R18 tires, the ETRTO recommended rim width is 7.5". The acceptable range is 6.5" minimum to 8.5" maximum. Using a rim outside this range can cause improper bead seating and unsafe handling.
Yes, as long as the replacement tire overall diameter is within 3% of the 225/40R18 637.2mm diameter. Compatible alternatives include 165/70R16, 215/30R20, 185/35R20. Use our Tire Size Calculator to compare any two sizes.