Fidamen

Convert Liters per 100 Kilometers to Gallons per 100 Miles - Fuel Economy Converter

This converter translates vehicle fuel consumption reported as litres per 100 kilometres (L/100 km) into US gallons per 100 miles (gal/100 mi). Both metrics express volume consumed over a fixed distance; this tool applies precise unit definitions to preserve accuracy for engineering, regulatory reporting, and consumer comparisons.

The conversion relies on internationally recognized definitions: the litre (derived from the SI) and the US liquid gallon, combined with the exact kilometre–mile relationship. Values shown are based on standard unit constants to support repeatability and traceability in measurements.

Use this converter to compare manufacturer or regulatory figures, convert fleet reports, or translate your vehicle's consumption for travel planning. See methodology and citations below for the exact constants and references used.

Updated Nov 20, 2025QA PASS — golden 25 / edge 120Run golden-edge-2026-01-23

Governance

Record 95d7162ea666 • Reviewed by Fidamen Standards Committee

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Methodology

Convert the volume component using the official litre-to-US-gallon factor defined by commonly referenced metrology sources, then adjust the distance basis from 100 kilometres to 100 miles using the exact kilometre–mile ratio.

We use the definition 1 litre = 0.264172052358148 US gallons (commonly adopted in metrology references) and the exact international length relationship 1 mile = 1.609344 kilometres. Multiplying these constants yields a stable conversion factor.

This approach preserves dimensional consistency (volume per distance) and is appropriate for engineering-level reporting. For field measurements, allow for instrument tolerances and rounding conventions used by regulators or fleet software.

Key takeaways

This conversion uses stable, published constants for litre-to-US-gallon and kilometre-to-mile conversions to produce repeatable gal/100 mi results from L/100 km inputs.

Apply instrument calibration allowances and rounding rules where required by regulation or reporting standards; see FAQs for calibration and accuracy guidance.

Worked examples

Example 1: 6.0 L/100 km → 6.0 × 0.425143707 ≈ 2.5509 gal/100 mi.

Example 2: 8.5 L/100 km → 8.5 × 0.425143707 ≈ 3.6137 gal/100 mi.

F.A.Q.

Does this convert to US gallons or imperial gallons?

This converter produces US liquid gallons per 100 miles (gal/100 mi). If you need imperial gallons, convert separately using the imperial gallon factor; imperial gallons and US gallons differ by volume (1 imperial gallon ≈ 1.20095 US gallons).

How precise is the conversion factor?

The factor is derived from exact international mile–kilometre relationship (1 mi = 1.609344 km) and the commonly used litre-to-US-gallon factor. It is suitable for engineering, fleet reporting, and consumer comparisons; round results according to your reporting precision (typically 3 significant digits for consumer display, more for engineering).

Why would I use gallons per 100 miles instead of miles per gallon (MPG)?

Gal/100 mi, like L/100 km, is a 'consumption' metric (volume per fixed distance) and is linearly proportional to fuel used. MPG is an efficiency metric (distance per unit volume) and is non-linear when converting from consumption. Use consumption metrics when comparing fuel used for trips or projecting fuel costs.

How should I account for measurement and instrument limits?

On-board meters, fuel pumps, and tank-level sensors have tolerances and may introduce bias. For vehicle-level reporting, calibrate sensors against measured refueling volumes and odometer-verified distances. For regulatory reporting, follow the instrument accuracy requirements in relevant standards or agency guidance.

Can I use this for fuel-cost estimates?

Yes—after converting consumption to a preferred unit, multiply gal/100 mi by fuel price per gallon and scale to your trip distance. Remember to include rounding and any taxes or fees applied at the pump.

Are the constants here traceable to authoritative sources?

Yes. The conversion uses internationally established unit definitions and widely published conversion constants used in metrology and government guidance. See citations for links to US government and metrology references.

Sources & citations

Further resources

Versioning & Change Control

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

Record ID: 95d7162ea666

What changed (latest)

v1.0.0 • 2025-11-20 • 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 20, 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 • 2025-11-20 • 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: 6c6e11326dfc