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L/100km to MPG Calculator

Convert metric fuel consumption to US miles per gallon for plant and vehicle running costs.

Computed in your browser — nothing you enter is uploaded. Figures are presented for United States against IRC 2024, and every formula is cited under regulatory standards below.

Last verified 2026-08-26 · v1.0.0

Market
Imperial · sales tax

Fuel economy

23.52 US MPG

High confidence

MPG = 235.215 ÷ (L/100km). The two are reciprocal measures, not proportional ones. Imperial MPG uses a different constant — a UK figure and a US figure for the same vehicle will not match.

Fleet and plant running costs cross this boundary whenever equipment is specified in one market and operated in another. The conversion is a reciprocal rather than a multiplier, which is the part that trips people up: litres per hundred kilometres measures consumption where less is better, while miles per gallon measures economy where more is better, so the relationship inverts. Halving fuel consumption doubles the MPG figure. The other reliable confusion is which gallon: US MPG uses a constant of 235.2 and imperial MPG 282.5, so identical vehicles score about twenty percent apart depending on which convention the figure came from, and UK published figures are almost always imperial.

Add the equipment this sizes

This result is a specification — 23.521 US MPG — not a quantity. Put the thing it sizes into your project: how many, what you call it, and your supplier’s price.

Preliminary estimate, not certified engineering. This tool produces an indicative quantity calculation for planning purposes only — it is not a certified structural analysis, a guaranteed material takeoff, or a substitute for building department approval. Always verify measurements on-site and have a licensed contractor or structural engineer review any load-bearing, code-sensitive, or safety-critical work before purchasing materials or starting construction. Spotted an arithmetic or standards error? Report it to contact@craftquantities.com with your inputs — confirmed fixes become pinned regression tests.

[Schema Verified] Computed in alignment with American Concrete Institute (ACI 318-19) formulas and International Residential Code (IRC 2024) spatial boundaries.

Regulatory standards & verification citations

  • US MPG = 235.214583 / (L/100km), derived from 1 US gallon = 3.785411784 L and 1 mile = 1.609344 km
  • Imperial MPG uses 282.481 instead, because an imperial gallon is larger

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Frequently asked questions

Why is this a division rather than a multiplication?
Because the two measures run in opposite directions. Litres per 100 km is consumption — lower is better. MPG is economy — higher is better. They are reciprocals, so halving consumption doubles MPG rather than halving it.
US or imperial MPG?
This gives US MPG. Imperial MPG uses a constant of 282.481 because an imperial gallon is about twenty percent larger, so the same vehicle scores noticeably higher in imperial figures. UK quoted figures are usually imperial.
Does this apply to plant as well as vehicles?
Only to plant measured over distance. Excavators and generators consume by the hour rather than the mile, so their running costs are worked out from litres per hour, which is a different measure entirely.