米ガロンと英ガロンに対応し、mpg、L/100 km、km/L を相互換算します。式：L/100 km = 235.215 ÷ US mpg または 282.481 ÷ UK mpg。
更新日 検証済みの例：4
30 mpg (US)は約7.840486 L/100 kmです。 一方の単位は距離あたりの燃料、他方は燃料あたりの距離を表すため、一方の数値が大きくなると他方は小さくなります。
| 単位 | 値 | 定義 |
|---|---|---|
| キロメートル毎リットル (km/L) | 12.75431 | 基本単位 |
| 100キロメートル当たりリットル (L/100 km) | 7.840486 | km/L = 100 ÷ (L/100 km)、正確な値 |
| マイル毎米ガロン (mpg (US)) | 30 | 1 mpg (US) = 1.609344/3.785411784 km/L、正確な値 |
| マイル毎英ガロン (mpg (UK)) | 36.0285 | 1 mpg (UK) = 1.609344/4.54609 km/L、正確な値 |
1 mpg (US) = 1.609344/3.785411784 km/L、正確な値
km/L = 100 ÷ (L/100 km)、正確な値
L/100 kmは距離あたりの燃料消費量、mpg (US)は燃料の単位量あたりの走行距離を表します。両者は反比例し、積は常に235.2146です。一方が2倍になると、もう一方は半分になります。
両方の単位の定義は正確ですが、変換後の値は循環小数です。有効数字12桁で表示します。
Fuel economy comes in two shapes. Miles per gallon and kilometres per litre measure distance per unit of fuel; litres per 100 km measures fuel per distance. The two are reciprocals, so L/100 km = 100 ÷ (km/L), and a US mpg figure converts as L/100 km = 235.215 ÷ mpg.
The default converts 30 US mpg to 7.84 L/100 km. Comparing cars across markets is the usual reason: the US quotes mpg with a 3.785 L gallon, the UK quotes mpg with a 4.546 L gallon while selling fuel by the litre, most of Europe uses L/100 km and India uses km/L.
Because the scales are reciprocal, equal steps in mpg are not equal fuel savings: going from 10 to 20 mpg saves 5 gallons per 100 miles, while going from 30 to 50 mpg saves 1.33. The chart plots that curve.
照合元：100 ÷ (30 × 1.609344 km / 3.785411784 L) = 112903/14400 (Python 3.8 fractions from the legal definitions)
照合元：(100 / 10) km/L ÷ (1.609344/3.785411784) = 112903/4800 (Python 3.8 fractions from the legal definitions)
照合元：40 × 3.785411784 / 4.54609 (Python 3.8 fractions from the legal definitions)
照合元：100 / 10 = 10 — the one value where km/L and L/100 km coincide
Divide 235.215 by a US mpg figure, or 282.481 by a UK mpg figure. 30 US mpg is 7.84 L/100 km and 50 UK mpg is 5.65 L/100 km. The constants are 100 × 3.785411784 ÷ 1.609344 and 100 × 4.54609 ÷ 1.609344, built from the exact gallon and mile.
Because the imperial gallon is 20% larger: 4.54609 L against 3.785411784 L. A car doing 40 mpg on UK figures does 33.3 mpg in US gallons, and 40 US mpg is 48.0 UK mpg. Both describe the same fuel use; 40 UK mpg is 7.06 L/100 km.
Because fuel used is distance divided by mpg. Over 100 miles, 10 mpg burns 10 gallons and 20 mpg burns 5, a saving of 5; 30 mpg burns 3.33 and 50 mpg burns 2, a saving of 1.33. Larrick and Soll called this the “MPG illusion” (Science, 2008); L/100 km avoids it because it measures fuel directly.
Divide 100 by the km/L figure: 20 km/L is 5 L/100 km and 12.5 km/L is 8 L/100 km. At 10 km/L the two numbers are equal. To go from km/L to US mpg, multiply by 2.35215, so 15 km/L is 35.3 US mpg.
Yes. L/100 km counts fuel used, so a smaller number means less fuel: 5 L/100 km is twice as economical as 10 L/100 km. With mpg and km/L a larger number is better. The product of the two stays fixed, 235.215 for L/100 km and US mpg, which is why one falls as the other rises.
精度は入力値と計算方法の前提に依存します。十進演算には有効数字50桁を使いますが、推定、数値計算手法、元データの精度はそれより低い場合があります。表示の丸め処理でこれらの制約がなくなるわけではありません。 独立した出典の解答と照合した計算例：4。 例えば、「30 mpg (US) in L/100 km」は100 ÷ (30 × 1.609344 km / 3.785411784 L) = 112903/14400 (Python 3.8 fractions from the legal definitions)と照合しています。
NIST SP 811 (2008), Guide for the Use of the SI, Appendix B — conversion factors; NIST Handbook 44, Appendix C — General tables of units of measurement.
この計算機には、独立した出典の解答を使った計算例が 4 件あります。テストに組み込まれており、ここでも実行できます。