Fidamen

Convert Kilometers per Liter to Liters per 100 Kilometers - Fuel Economy Converter

This converter transforms fuel economy expressed in kilometres per litre (km/L) into litres consumed per 100 kilometres (L/100 km), a common metric used in regulatory reporting and vehicle comparison in many countries.

The conversion is a fixed mathematical inversion widely used by engineering teams and government agencies to compare vehicle fuel consumption on a uniform scale.

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

Governance

Record 6adb4253ccc3 • Reviewed by Fidamen Standards Committee

Interactive converter unavailable for this calculator.

We could not resolve compatible units for this experience. Please verify the slug follows the pattern `from-unit-to-unit-converter`.

Methodology

The conversion uses a direct reciprocal relationship between the two units: one measures distance traveled per unit of fuel (km/L) and the other measures fuel used per fixed distance (L/100 km). Multiply the reciprocal of km/L by 100 to express fuel use per 100 kilometres.

This approach aligns with measurement conventions used by national laboratories and transport agencies. For presentation we recommend reporting results to two or three decimal places depending on the precision of the input data and the instrument accuracy.

Key takeaways

Conversion is exact and reversible (L/100 km = 100 ÷ (km/L); km/L = 100 ÷ (L/100 km)).

Use this converter for quick unit translations when comparing fuel economy figures from different sources or regulations.

Worked examples

Example 1: 15.0 km/L → L/100 km = 100 ÷ 15.0 = 6.666... → report 6.667 L/100 km (3 dp).

Example 2: 8.5 km/L → L/100 km = 100 ÷ 8.5 = 11.7647 → report 11.765 L/100 km (3 dp).

Example 3: 0.0 km/L is undefined — the conversion requires a positive km/L value (vehicle not moving or infinite consumption cannot be converted).

F.A.Q.

What is the exact mathematical relationship between km/L and L/100 km?

They are reciprocal measurements scaled to 100 km. L/100 km = 100 ÷ (km per L). Conversely, km/L = 100 ÷ (L per 100 km).

How many decimal places should I report?

For consumer-facing displays, 2–3 decimal places are typical. For regulatory or engineering work, follow the precision rules in the applicable test procedure or dataset. If your input comes from an onboard trip computer, match the device's reported precision.

Can I convert zero or negative values?

No. The conversion requires a positive km/L value. Zero or negative inputs are physically invalid for fuel economy and will not produce a meaningful L/100 km result.

Why might my vehicle's onboard computer and this calculator give slightly different results?

Differences arise from measurement windows, sensor calibration, rounding, and whether the onboard system uses estimated fuel flow versus tank-burn measurements. Regulatory test cycles and lab measurements use controlled procedures that differ from real-world onboard averaging.

How does this conversion relate to regulatory reporting?

Transport and environment agencies publish fuel consumption and greenhouse gas metrics in L/100 km for broad comparability. Use the converted number as a unit-aligned value but follow the specific test or reporting protocol when submitting regulatory data.

How do I convert from imperial MPG to L/100 km?

First convert MPG (US or UK) to km/L using the appropriate factor for the MPG variant, then apply L/100 km = 100 ÷ (km/L). Use authoritative conversion factors from national metrology institutes or government fuel-economy publications for precise work.

Does temperature, altitude, or fuel quality affect the conversion?

The mathematical conversion is unaffected by conditions. However, those factors influence actual fuel consumption measurements; account for them when interpreting real-world fuel-economy figures.

Is this converter suitable for high-precision engineering analyses?

The conversion is exact, but the accuracy of the result depends on the input's measurement quality. For engineering or certification work, use instrument-calibrated data and follow the precision and uncertainty requirements from standards bodies.

Sources & citations

Further resources

Versioning & Change Control

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

Record ID: 6adb4253ccc3

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: 2b21b880f93a