Fidamen

Convert UK Gallons to Liters – Volume Converter

This tool converts volumes expressed in UK (Imperial) gallons to liters. The Imperial (UK) gallon is the traditional gallon used in the United Kingdom and some Commonwealth countries; it differs from the US liquid gallon. Use this converter when you need a quick, standards-informed numeric conversion for documentation, calculation, or unit label purposes.

The conversion implemented here uses the internationally accepted definition of the Imperial gallon expressed in liters. The conversion factor is exact by definition; guidance is included below on practical rounding, measurement uncertainty, and calibration for regulatory or engineering work.

Updated Nov 14, 2025QA PASS — golden 25 / edge 120Run golden-edge-2026-01-23

Governance

Record 65d35fdc556d • Reviewed by Fidamen Standards Committee

Interactive Converter

Convert between uk gallon (imperial) and liter with precision rounding.

Quick reference table

UK Gallon (Imperial)Liter
1 gal_uk4.5461 L
5 gal_uk22.7305 L
10 gal_uk45.4609 L
25 gal_uk113.6523 L
50 gal_uk227.3045 L
100 gal_uk454.609 L

Methodology

The converter applies the defined relationship between the Imperial (UK) gallon and the liter. By international definition the Imperial gallon equals 4.54609 liters, and the conversion is a direct multiplication: liters = gallons (UK) × 4.54609. This is a fixed mathematical relationship; no empirical estimation is used.

For measurement traceability and legal metrology considerations, reported or recorded volumes should reflect the measurement instrument's calibrated uncertainty. Follow traceability and calibration practices recommended by national metrology institutes and international standards such as NIST guidance and ISO 80000 where applicable. When using converted figures in trade, labeling, or regulatory filings, retain original measurement records and calibration certificates as required by local weights-and-measures authorities.

Worked examples

1 UK gallon → 4.54609 L (exact by definition)

2.5 UK gallons → 11.365225 L → recommend display 11.3652 L (4 decimal places) or 11.37 L (2 decimal places) depending on use

10 UK gallons → 45.4609 L (show as 45.4609 L for technical reporting)

F.A.Q.

Is the UK (Imperial) gallon different from the US gallon?

Yes. The UK (Imperial) gallon is larger. One Imperial (UK) gallon equals 4.54609 liters. One US liquid gallon equals 3.785411784 liters. Use the correct gallon type when converting to liters.

Is the conversion factor exact or approximate?

The conversion factor used here (1 UK gallon = 4.54609 liters) is the defined factor and should be treated as exact for unit conversion. However, when converting measured volumes, the overall uncertainty depends on instrument accuracy and calibration.

How many decimal places should I display?

Choose decimal places to reflect measurement uncertainty and regulatory requirements. For general purposes 2 decimal places are typical. For laboratory or engineering work 3–4 decimals or more may be appropriate, but never present more precision than supported by the underlying measurement.

Do I need calibration certificates when using converted volumes for trade?

Yes. For trade, labeling, or compliance, keep original measurement records and calibration documentation as required by local weights-and-measures authorities. Conversion alone does not substitute for traceable calibration.

Can I convert backward from liters to UK gallons with this factor?

Yes. Use the inverse relationship: UK_gallons = liters ÷ 4.54609. Ensure you use the Imperial gallon definition when converting back.

Sources & citations

Further resources

Versioning & Change Control

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

Record ID: 65d35fdc556d

What changed (latest)

v1.0.0 • 2025-11-14 • 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 14, 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 • 2025-11-14 • 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: e8ac1d2fc984