How many liters and gallons of air does a tire hold?
A 225/45R17 car tire holds about 30.0 liters (7.9 US gallons) of air. A 265/70R17 pickup tire holds about 74.9 liters (19.8 gallons) and a 35x12.50R17 about 118.3 liters (31.2 gallons). These are calculated from the tire's outside dimensions, so the real air space is somewhat smaller.
Quick select:
Air Volume
29.96L
Liters
29.96
L
Cubic Inches
1828.5
in³
Cubic Feet
1.0581
ft³
Formula
V = (π² ÷ 2) × W × H × R_center
W = 225 mm · H = 101.3 mm (sidewall) · R_center = 266.5 mm
Calculated from the tire's outside dimensions. The real air space is smaller, because tread and sidewall rubber take up part of it.
Get a plain-English explanation of your results and what they mean for your vehicle.
Tire Air Volume by Size
| Tire size | Liters | US gallons | Cubic inches | Cubic feet |
|---|---|---|---|---|
| 195/65R15 | 31.0 | 8.2 | 1,890 | 1.09 |
| 205/55R16 | 29.6 | 7.8 | 1,807 | 1.05 |
| 225/45R17 | 30.0 | 7.9 | 1,828 | 1.06 |
| 245/40R18 | 32.9 | 8.7 | 2,007 | 1.16 |
| 235/55R18 | 44.0 | 11.6 | 2,682 | 1.55 |
| 275/40R19 | 44.2 | 11.7 | 2,699 | 1.56 |
| 235/65R16 | 49.5 | 13.1 | 3,022 | 1.75 |
| 225/75R16 | 53.9 | 14.2 | 3,288 | 1.90 |
| 265/70R17 | 74.9 | 19.8 | 4,569 | 2.64 |
| 315/70R17 | 111.8 | 29.5 | 6,822 | 3.95 |
| 35x12.50R17 | 118.3 | 31.2 | 7,217 | 4.18 |
Calculated with the formula below. No tire maker or standards body publishes air volume by size that we could find, so these are not published values.
Air Volume by Vehicle Type
| Vehicle type | Example size | Liters | US gallons |
|---|---|---|---|
| Compact car | 195/65R15 | 31.0 | 8.2 |
| Sedan | 225/45R17 | 30.0 | 7.9 |
| SUV | 235/55R18 | 44.0 | 11.6 |
| Van or light truck | 225/75R16 | 53.9 | 14.2 |
| Pickup truck | 265/70R17 | 74.9 | 19.8 |
How to Use This Calculator
- Enter the section width in mm, the aspect ratio and the rim diameter in inches, for example 225, 45 and 17.
- Read the air volume in liters, cubic inches and cubic feet.
- Divide the liters by 3.785 for US gallons.
- Change one number to compare a second size.
Formula
About Tire Air Volume
Tire air volume is the space inside a mounted tire that air fills. It depends on the section width, the sidewall height and the rim diameter.
What the number is used for
- Comparing sizes. A wider tire, a taller sidewall or a larger rim each add air volume.
- Air supply. To fill an empty tire to a gauge pressure, free air needed = volume × (gauge psi + 14.7) ÷ 14.7. A 30.0 liter tire filled to 35 psi needs about 101 liters of free air.
- Sealant. Dose by the sealant maker's label for your tire size. This page gives no percentage rule because we found none published.
How the number is calculated
The calculator treats the tire cross-section as an ellipse and sweeps it around the wheel, using only the size marking. Tread and sidewall rubber occupy part of the outside envelope, so the real air space is smaller than the result.
Related checks
- Pressure is a separate question from volume. The tire pressure calculator covers it, and the kPa to PSI converter handles a gauge or air system in metric units.
- For the footprint at a given pressure, see the tire contact patch estimator.
- To turn a size such as 35x12.50R17 into a metric size, use the inch to metric tire size chart.