Cubic Inches to US Gallons Converter

Convert cubic inches to US liquid gallons (and back) instantly with common volume reference points.

Volume Converter

Common Reference Points

Volume in³ US gal

Conversion Formula

in³ → gal gal = in³ ÷ 231
gal → in³ in³ = gal × 231

The factor 231 is the exact legal definition of the US liquid gallon (NIST Handbook 44).

Summary

Convert cubic inches to US liquid gallons (and back) instantly with common volume reference points.

How it works

  1. Enter a value in cubic inches or US gallons.
  2. The converter applies the exact factor: 1 US gal = 231 in³.
  3. The opposite field updates instantly as you type.
  4. Reference cards below the converter show common volume benchmarks.
  5. Click "Swap" to reverse the direction of conversion.

Use cases

  • Calculate fuel tank capacity from engine displacement specs.
  • Convert aquarium or reservoir volume for water treatment.
  • Verify industrial container volumes during manufacturing.
  • Cross-check automotive or marine engine specs in different units.
  • Convert recipe or storage volumes between unit systems.

Frequently Asked Questions

Last updated: 2026-06-09 · Reviewed by Nham Vu