Conversion
Cubic Inches to US gallons
1 in³ = 0.004329 US gal, derived from exact unit definitions.
—
Swap ⇆| in³ | US gal |
|---|---|
| 100 in³ | 0.4329 US gal |
| 231 in³ | 1.0000 US gal |
| 500 in³ | 2.1645 US gal |
| 1,000 in³ | 4.3290 US gal |
| 5,000 in³ | 21.6450 US gal |
| 10,000 in³ | 43.2900 US gal |
| 57,750 in³ | 250.0000 US gal |
Formula
US gallons = cubic inches × 0.004329004329FAQ
How many US gallons in a cubic inche?
1 in³ = 0.004329 US gal. Multiply your cubic inches value by 0.004329.
Is this exact?
Yes — these factors derive from exact definitions: 1 US gallon = 231 cubic inches, 1 imperial gallon = 4.54609 liters, 1 inch = 2.54 cm, 1 barrel = 42 US gallons.
Why do tank specs mix cubic inches and US gallons?
US tank trade uses gallons and inches; engineering drawings and international suppliers use metric or cubic measures. This page bridges them without rounding drift.