Convert Cubic Inches to Imperial Gallons
1 cubic inch (in³) equals 0.00360465015 imperial gallons (gal (imp)).
1 in³ = 0.00360465015 gal (imp)
Type in either box. Scientific notation works: 1.5e-3.
Converting a list? Use the bulk cubic inch to imperial gallon converter to paste a column from Excel.
How to Convert Cubic Inch to Imperial Gallon
- 1 in³ = 0.00360465015 gal (imp)
- 1 gal (imp) = 277.4194328 in³
- Example: convert 15 in³ to gal (imp): 15 in³ = 15 × 0.00360465015 gal (imp) = 0.05406975225 gal (imp)
Formula
gal (imp) = in³ × 0.003604650149909
or gal (imp) = in³ ÷ 277.4194327916
Derivation from SI units:
- 1 in³ = (0.0254 m)³ = 1.6387064 × 10⁻⁵ m³ = 16.387064 cm³
- 1 imp gal = 4.54609 L = 0.00454609 m³ (exact, by definition)
- 1 in³ = 0.000016387064 m³ ÷ 0.00454609 m³ per gal (imp) = 0.003604650149909 gal (imp)
Both units are defined exactly, so the factor is exact. Cubic Inch definition: cubic inch; Imperial Gallon definition: imperial gallon.
Worked examples
- A reading of 61.024 in³ converts to 0.2199701707 gal (imp).
61.024 in³ × 0.00360465015 = 0.2199701707 gal (imp) - A value of 350 in³ is 1.261627552 gal (imp).
350 in³ × 0.00360465015 = 1.261627552 gal (imp)
Cubic Inch to Imperial Gallon conversion table
| Cubic Inches (in³) | Imperial Gallons (gal (imp)) |
|---|---|
| 1 in³ | 0.00360465015 gal (imp) |
| 5 in³ | 0.01802325075 gal (imp) |
| 10 in³ | 0.0360465015 gal (imp) |
| 25 in³ | 0.09011625375 gal (imp) |
| 50 in³ | 0.1802325075 gal (imp) |
| 61.024 in³ | 0.2199701707 gal (imp) |
| 100 in³ | 0.360465015 gal (imp) |
| 231 in³ | 0.8326741846 gal (imp) |
| 250 in³ | 0.9011625375 gal (imp) |
| 302 in³ | 1.088604345 gal (imp) |
| 350 in³ | 1.261627552 gal (imp) |
| 427 in³ | 1.539185614 gal (imp) |
| 454 in³ | 1.636511168 gal (imp) |
| 500 in³ | 1.802325075 gal (imp) |
| 1000 in³ | 3.60465015 gal (imp) |
| 1728 in³ | 6.228835459 gal (imp) |
Where it's used
Cubic Inches are used for US engine displacement (e.g. 350 cubic inches ≈ 5.7 L), while imperial gallons appear in fuel economy in the UK (miles per gallon). Both measure volume (capacity), so the conversion is a fixed factor.
Cubic Inch to other volume units
| Conversion | 1 in³ equals |
|---|---|
| cubic inch to cubic meter | 0.000016387064 m³ |
| cubic inch to liter | 0.016387064 L |
| cubic inch to milliliter | 16.387064 mL |
| cubic inch to cubic centimeter | 16.387064 cm³ |
| cubic inch to cubic foot | 0.0005787037037 ft³ |
| cubic inch to US gallon | 0.004329004329 gal (US) |
| cubic inch to imperial gallon | 0.00360465015 gal (imp) |
Frequently asked questions
How many imperial gallons are in 1 cubic inch?
1 in³ = 0.00360465015 gal (imp).
How do I convert cubic inches to imperial gallons?
Multiply the value in in³ by 0.00360465015, or divide it by 277.4194328. For example, 15 in³ × 0.00360465015 = 0.05406975225 gal (imp).
Is the in³ to gal (imp) conversion exact?
Yes. Both units are defined exactly, so the ratio is exact; its decimal form does not terminate and is shown here to 10 significant figures (more with the precision selector).
Sources
- Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "cubic inch (in³)".
- Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "gallon [Canadian and U.K. (Imperial)]".
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
Cite this page
APA
Scientific Converters. (2026, October 15). Convert Cubic Inches to Imperial Gallons. Retrieved October 17, 2026, from https://scientificconverters.com/volume/cubic-inches-to-imperial-gallons/
IEEE
Scientific Converters, "Convert Cubic Inches to Imperial Gallons," scientificconverters.com. Accessed: Oct. 17, 2026. [Online]. Available: https://scientificconverters.com/volume/cubic-inches-to-imperial-gallons/