225/45R18 Tire Size
Dimensions of a 225/45R18 tire in inches and millimeters, with equivalent and plus sizes.
225/45R18 dimensions
A 225/45R18 tire is 225 mm wide with a sidewall that is 45% of the width (101 mm), mounted on a 18-inch rim. Its overall diameter is about 25.97 inches (660 mm), so it is roughly a 26.0-inch tall tire.
| Overall diameter | 25.97 in | 660 mm |
|---|---|---|
| Section width | 8.86 in | 225 mm |
| Sidewall height | 3.99 in | 101.2 mm |
| Rim diameter | 18 in | 457 mm |
| Circumference | 81.6 in | 2073 mm |
| Revolutions | 777 per mile | 483 per km |
Equivalent sizes on a 18-inch rim
These sizes stay within ±3% of the 225/45R18 diameter on the same rim — the range most tire shops use. Not every size is made in every tire model, and only sizes approved for your vehicle (with the right load and speed rating) should be fitted.
| Size | Diameter | mm | Difference |
|---|---|---|---|
| 205/50R18 | 26.07 in | 662 mm | +0.4% |
| 245/40R18 | 25.72 in | 653 mm | -1.0% |
| 235/45R18 | 26.33 in | 669 mm | +1.4% |
| 215/45R18 | 25.62 in | 651 mm | -1.4% |
| 215/50R18 | 26.46 in | 672 mm | +1.9% |
| 235/40R18 | 25.40 in | 645 mm | -2.2% |
| 205/45R18 | 25.26 in | 642 mm | -2.7% |
| 245/45R18 | 26.68 in | 678 mm | +2.7% |
Plus and minus sizes
Changing the rim size? These options on 17-, 19- and 20-inch rims keep the overall diameter within ±3%.
| Size | Diameter | mm | Difference |
|---|---|---|---|
| 215/35R20 | 25.93 in | 658 mm | -0.2% |
| 255/30R20 | 26.02 in | 661 mm | +0.2% |
| 255/35R19 | 26.03 in | 661 mm | +0.2% |
| 255/45R17 | 26.04 in | 661 mm | +0.2% |
| 225/40R19 | 26.09 in | 663 mm | +0.4% |
| 225/50R17 | 25.86 in | 657 mm | -0.4% |
| 245/30R20 | 25.79 in | 655 mm | -0.7% |
| 215/40R19 | 25.77 in | 655 mm | -0.8% |
| 245/35R19 | 25.75 in | 654 mm | -0.8% |
| 225/35R20 | 26.20 in | 666 mm | +0.9% |
Compare 225/45R18 with another size →
Frequently asked questions
How tall is a 225/45R18 tire?
About 25.97 inches (660 mm) in overall diameter.
How wide is a 225/45R18 tire?
The section width is 225 mm, about 8.9 inches.
What size can replace 225/45R18?
On the same rim, 205/50R18 is the closest size (+0.4% diameter). Use only sizes approved for your vehicle.
How many revolutions per mile does a 225/45R18 tire make?
About 777 revolutions per mile (483 per km).
More lease calculators
Car leasing
- Car Lease CalculatorEnter the numbers from the dealer quote to see your monthly lease payment — and exactly where every dollar goes.Open calculator →
- Lease Deal CheckerType in the numbers from the dealer's quote. We grade the deal, reveal the money factor hidden in the payment and flag anything worth negotiating.Open calculator →
- Money Factor to APR CalculatorType a money factor or an APR — the other updates instantly. Add your contract numbers to find your real rate and any markup.Open calculator →
- Lease Buyout CalculatorFind out what it really costs to buy your leased car and whether it is worth more than the buyout.Open calculator →
- Lease vs Buy Car CalculatorCompare the true cost of leasing versus buying the same car, counting the value of the car you would own.Open calculator →
- Lease Mileage CalculatorFind out if you will go over your lease miles, what it could cost, and how much you can still drive each month.Open calculator →
- Early Lease Termination CalculatorCompare the three ways out of a car lease — return it early, sell it, or keep it — and see roughly what each one costs.Open calculator →
- Lease Equity CalculatorSee if your leased car is worth more than you owe — and what negative equity would add to your next lease.Open calculator →
Buying & car loans
- Car Payment CalculatorWork out the monthly payment on an auto loan — with tax, trade-in and fees — and see how much interest you will pay.Open calculator →
- Car Affordability CalculatorStart from the monthly payment you are comfortable with and see the most you should spend on a car.Open calculator →
- Auto Refinance CalculatorSee whether refinancing your car loan really saves money — not just a lower payment, but less paid in total.Open calculator →
- Car Loan Payoff CalculatorFind out how much faster you can pay off your car — and how much interest you save — with extra payments.Open calculator →
- Out-the-Door Price CalculatorTurn the sticker price into the real amount you will pay: sales tax, dealer fees, title and registration included.Open calculator →
- Balloon Payment CalculatorFind the monthly payment on a car loan with a lump sum at the end — and how much extra interest it costs.Open calculator →
- PCP CalculatorWork out the monthly cost of Personal Contract Purchase car finance and compare it with hire purchase.Open calculator →
- Car Depreciation CalculatorSee how much value a car loses each year and what it may be worth when you sell, trade in or reach lease end.Open calculator →
Running costs & taxes
- Fuel Cost CalculatorFind out how much gas a trip will cost — and how much each person owes if you share the ride.Open calculator →
- Gas Mileage Calculator (MPG)Measure your car's real fuel economy from one full tank and convert it between mpg and L/100 km.Open calculator →
- EV Charging Cost CalculatorSee what it costs to charge an electric car each month — and compare it with filling up a gas car.Open calculator →
- Mileage Reimbursement CalculatorCalculate what your miles are worth at the 2026 IRS standard rates — or your employer's rate — and compare with what you spend on gas.Open calculator →