Tire Height Calculator
Enter your tire specs (e.g., 245/45R18)
Total Tire Diameter:
0.00 in
Total Tire Diameter:
0.00 mm
Sidewall Height:
0.00 in
Circumference:
0.00 in
Understanding Tire Height and Dimensions
Whether you are upgrading your wheels, looking for better off-road clearance, or simply curious about your vehicle's stance, knowing your exact tire height is essential. Tire sizes are written in a specific alphanumeric format (like 245/45R18) that hides the actual physical dimensions of the rubber.
How to Read Tire Numbers
The numbers on your tire's sidewall represent three distinct measurements:
- Section Width: The first number (e.g., 245) is the width of the tire in millimeters from sidewall to sidewall.
- Aspect Ratio: The second number (e.g., 45) is a percentage. It tells you that the height of the sidewall is 45% of the section width.
- Rim Diameter: The final number (e.g., 18) is the diameter of the wheel in inches.
The Tire Height Formula
To calculate the total height (diameter) of a tire manually, you use the following math:
Height = ((Width × Aspect Ratio / 100) × 2 / 25.4) + Rim Diameter
We multiply the sidewall height by two because the total diameter includes the sidewall at the top and the bottom of the wheel.
Common Tire Height Examples
| Tire Size | Total Height (Inches) |
|---|---|
| 215/55R17 | 26.31″ |
| 265/70R17 | 31.61″ |
| 245/40R19 | 26.72″ |
Why Tire Height Matters
Changing your tire height affects your vehicle's performance in several ways:
- Speedometer Accuracy: A taller tire covers more ground in one revolution. If you install taller tires, your speedometer will read slower than you are actually traveling.
- Gear Ratio: Larger tires effectively "lengthen" your gears, which can lead to slower acceleration but potentially better fuel economy at highway speeds.
- Clearance: Oversized tires can rub against the wheel wells or suspension components during sharp turns or when hitting bumps.