Convert Gallons to Liters – Volume Converter
This converter translates volumes measured in US liquid gallons to liters using the internationally recognized definitions of the units. It is intended for everyday conversions, lab reporting, inventory tracking, and regulatory documentation where clear identification of the gallon type is required.
The tool uses the exact relationship between the US liquid gallon and the liter based on SI definitions of length and volume. Users who need conversions for other gallon definitions (for example imperial gallons) should use the appropriate converter or consult the notes below.
Results are presented with suggested rounding for readability but users should apply domain-specific rounding or uncertainty propagation for legal, trade, or laboratory reporting. See the methodology and FAQs for guidance on calibration, measurement uncertainty, and applicable standards.
Governance
Record 84accf74f7aa • Reviewed by Fidamen Standards Committee
Interactive Converter
Convert between us gallon and liter with precision rounding.
Quick reference table
| US Gallon | Liter |
|---|---|
| GAL 1.00 gal | 3.7854 L |
| GAL 5.00 gal | 18.9271 L |
| GAL 10.00 gal | 37.8541 L |
| GAL 25.00 gal | 94.6353 L |
| GAL 50.00 gal | 189.2705 L |
| GAL 100.00 gal | 378.541 L |
Methodology
Unit definitions follow international standards: the liter is a derived SI unit equal to one cubic decimeter and US liquid gallon is defined via cubic inches with the international inch to meter relationship. The numeric conversion factor is derived from these exact definitions.
We reference national and international standards and guidance for units and reporting to ensure traceability: NIST guidance on SI use and unit definitions, ISO 80000 series on quantities and units, and general standards bodies for reporting conventions.
This tool performs a deterministic multiplication by the exact conversion factor. It does not add measurement uncertainty; users responsible for compliance must include instrument calibration and uncertainty calculations per their sector standards.
Worked examples
Example 1: 1 US gallon → 1 × 3.785411784 = 3.785411784 L (commonly rounded to 3.7854 L for display).
Example 2: 5 US gallons → 5 × 3.785411784 = 18.92705892 L (round as required, for example 18.9271 L).
Example 3 (imperial context): 1 imperial gallon → 4.54609 L (use the imperial factor only when the source explicitly states imperial gallons).
F.A.Q.
Which gallon does this converter use?
This converter uses the US liquid gallon (often abbreviated gal US). If you need an imperial (UK) gallon conversion, use a converter that specifies the imperial gallon or apply the imperial factor of 4.54609 L per imperial gallon.
Is the conversion factor exact or approximate?
The numeric factor 3.785411784 for the US liquid gallon to liter conversion is derived from exact definitions (231 in3 and 0.0254 m per inch) and is conventionally used as the exact factor for conversion. Displayed results may be rounded for readability.
How should I handle rounding and reporting for regulatory or lab use?
Round and report according to your domain requirements and the applicable standard. For laboratory and legal reporting include measurement uncertainty, instrument calibration status, and significant figures according to your lab protocol, ISO guidance, or national metrology office recommendations.
Does this tool account for measurement uncertainty or temperature effects?
No. This converter performs a mathematical unit conversion only. It does not account for measurement uncertainty, thermal expansion of liquids, or instrument calibration. For precision work, calculate uncertainty per ISO/IEC 17025, NIST guidance, or your organization's procedures and apply temperature corrections as needed.
Can I convert fuel volumes or mass-to-volume using this tool?
This tool converts volume units only. Converting between mass and volume requires density at the relevant temperature and pressure. Refer to product-specific density data and use a density-based calculation to convert between mass and volume.
Sources & citations
- NIST Special Publication 811, Guide for the Use of the International System of Units (SI) — https://www.nist.gov/pml/special-publication-811
- ISO 80000 series — Quantities and units (overview) — https://www.iso.org/standard/30669.html
- IEEE Standards Association general information — https://standards.ieee.org
- Occupational Safety and Health Administration (OSHA) — official site — https://www.osha.gov
Further resources
Versioning & Change Control
Audit record (versions, QA runs, reviewer sign-off, and evidence).
Record ID: 84accf74f7aaWhat changed (latest)
v1.0.0 • 2025-11-13 • 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
Versioning & Change Control
Audit record (versions, QA runs, reviewer sign-off, and evidence).
What changed (latest)
v1.0.0 • 2025-11-13 • 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 13, 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 • 2025-11-13 • 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: 775d416828a8