Fidamen

Convert US Gallons to Liters – Volume Converter

This converter converts US liquid gallons to liters using the exact standards-based conversion factor. The US liquid gallon is defined by volume in cubic inches and international length and volume definitions, which makes the conversion to liters exact when using defined base units.

Use this tool for quick unit conversion, engineering checks, lab notes, shipping calculations, and regulatory reporting. For measurements taken in the field, see the accuracy and calibration guidance below to account for measurement uncertainty, temperature effects, and whether you are working with a liquid or a dry/product volume.

Updated Nov 15, 2025QA PASS — golden 25 / edge 120Run golden-edge-2026-01-23

Governance

Record 40a57f65456d • Reviewed by Fidamen Standards Committee

Interactive Converter

Convert between us gallon and liter with precision rounding.

Quick reference table

US GallonLiter
GAL 1.00 gal3.7854 L
GAL 5.00 gal18.9271 L
GAL 10.00 gal37.8541 L
GAL 25.00 gal94.6353 L
GAL 50.00 gal189.2705 L
GAL 100.00 gal378.541 L

Methodology

The conversion factor is derived from the international definitions that tie the inch to the metre and the litre to the cubic decimetre. Specifically, 1 US liquid gallon is defined as 231 cubic inches. With the inch defined exactly as 2.54 cm and 1 litre equal to 1,000 cubic centimetres, the conversion factor is exact under these definitions.

Standards referenced include NIST guidance on units and definitions and internationally recognized unit standards. For laboratory and compliance work, follow the relevant calibration and uncertainty guidance (for example ISO/IEC 17025 for laboratory calibration) and workplace safety guidance where volume quantities affect exposure or hazards.

Key takeaways

Use the exact factor 3.785411784 for conversions between US liquid gallons and liters when using standard unit definitions.

Confirm whether your gallon measurement is US liquid gallon, US dry gallon, or Imperial gallon before converting. This tool uses the US liquid gallon by default.

For compliance, calibration, and legal measurements, include measurement uncertainty and rely on calibrated instruments and applicable standards.

Worked examples

5 US gallons → 5 × 3.785411784 = 18.92705892 L (typical display: 18.9271 L with 4 decimal places).

0.1 US gallon → 0.3785411784 L (typical display: 0.3785 L).

1000 US gallons → 3,785.411784 L (display as needed depending on precision requirements).

F.A.Q.

Is the conversion factor exact?

Yes. Given the definitions used (1 US liquid gallon = 231 cubic inches; 1 inch = 2.54 cm exactly; 1 litre = 1000 cm³), the numeric factor 3.785411784 follows exactly from those definitions.

What is the difference between US liquid gallon, US dry gallon, and Imperial gallon?

The US liquid gallon (used here) is 231 cubic inches. A US dry gallon is different and rarely used; it is ≈4.40488377086 L. The Imperial gallon (used in some Commonwealth countries) is ≈4.54609 L. Verify which gallon definition applies to your data before converting.

How many decimal places should I display?

Display precision depends on use case: 4 decimal places is practical for many applications; lab work or financial reporting may require more. Always document the precision and include measurement uncertainty when required by standards.

Do I need to worry about temperature or density when converting?

The unit conversion itself is not temperature-dependent, but measured volumes of real liquids can vary with temperature and density. If converting mass to volume or comparing container filled volumes at different temperatures, account for thermal expansion and density changes using material-specific data.

Can I use this for legal or regulatory reporting?

This converter provides the mathematical unit conversion. For legal or regulatory reporting, follow the applicable standards and calibration procedures (for example ISO/IEC 17025 for lab calibration) and your regulator's prescribed rounding and uncertainty reporting rules.

Sources & citations

Further resources

Versioning & Change Control

Audit record (versions, QA runs, reviewer sign-off, and evidence).

Record ID: 40a57f65456d

What changed (latest)

v1.0.0 • 2025-11-15 • MINOR

Initial publication and governance baseline.

Why: Published with reviewed formulas, unit definitions, and UX controls.

Public QA status

PASS — golden 25 + edge 120

Last run: 2026-01-23 • Run: golden-edge-2026-01-23

Engine

v1.0.0

Data

Baseline (no external datasets)

Content

v1.0.0

UI

v1.0.0

Governance

Last updated: Nov 15, 2025

Reviewed by: Fidamen Standards Committee (Review board)

Credentials: Internal QA

Risk level: low

Reviewer profile (entity)

Fidamen Standards Committee

Review board

Internal QA

Entity ID: https://fidamen.com/reviewers/fidamen-standards-committee#person

Semantic versioning

  • MAJOR: Calculation outputs can change for the same inputs (formula, rounding policy, assumptions).
  • MINOR: New features or fields that do not change existing outputs for the same inputs.
  • PATCH: Bug fixes, copy edits, or accessibility changes that do not change intended outputs except for previously incorrect cases.

Review protocol

  • Verify formulas and unit definitions against primary standards or datasets.
  • Run golden-case regression suite and edge-case suite.
  • Record reviewer sign-off with credentials and scope.
  • Document assumptions, limitations, and jurisdiction applicability.

Assumptions & limitations

  • Uses exact unit definitions from the Fidamen conversion library.
  • Internal calculations use double precision; display rounding follows the unit's configured decimal places.
  • Not a substitute for calibrated instruments in regulated contexts.
  • Jurisdiction-specific rules may require official guidance.

Change log

v1.0.0 • 2025-11-15 • MINOR

Initial publication and governance baseline.

Why: Published with reviewed formulas, unit definitions, and UX controls.

Areas: engine, content, ui • Reviewer: Fidamen Standards Committee • Entry ID: 02fbc75fdb8a