# 연비 변환기 (mpg → L/100 km)

> 미국 및 영국 갤런 기준의 mpg, L/100 km, km/L를 서로 변환합니다. 공식: L/100 km = 235.215 ÷ US mpg 또는 282.481 ÷ UK mpg.

직접 계산할 수 있는 페이지: https://www.calcopenly.com/ko/conversion/fuel-economy-converter
분야: 단위 변환기

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.

## 입력

- **값**: 변환 전 단위의 숫자 또는 단위가 붙은 숫자를 입력하세요
- **변환 전** (선택 항목: kilometre per litre (km/L), litre per 100 km (L/100 km), mile per US gallon (mpg (US)), mile per imperial gallon (mpg (UK)))
- **변환 후** (선택 항목: kilometre per litre (km/L), litre per 100 km (L/100 km), mile per US gallon (mpg (US)), mile per imperial gallon (mpg (UK)))

## 결과

- 변환된 값 — 주요 결과
- 단위 변환
- 변환 계수
- 정확성

## 공식

$$
\begin{gathered} \text{L/100 km} = \dfrac{100}{\text{km/L}} \\ \text{km/L} = \text{mpg}_{\text{US}} \times \dfrac{1.609344}{3.785411784} = \text{mpg}_{\text{UK}} \times \dfrac{1.609344}{4.54609} \\ \text{L/100 km} \approx \dfrac{235.215}{\text{mpg}_{\text{US}}} \approx \dfrac{282.481}{\text{mpg}_{\text{UK}}} \end{gathered}
$$

## 계산 예제

### 30 mpg (US) in L/100 km

- 값: 30 mpg (US)
- 변환 전: mile per US gallon (mpg (US))
- 변환 후: litre per 100 km (L/100 km)
- **변환된 값: 7.8404861111 L/100 km**
- **정확성: 정의는 정확하며 순환소수임**
- 검증 출처: 100 ÷ (30 × 1.609344 km / 3.785411784 L) = 112903/14400 (Python 3.8 fractions from the legal definitions)

### 10 L/100 km in mpg (US)

- 값: 10 L/100 km
- 변환 전: litre per 100 km (L/100 km)
- 변환 후: mile per US gallon (mpg (US))
- **변환된 값: 23.5214583333 mpg (US)**
- 검증 출처: (100 / 10) km/L ÷ (1.609344/3.785411784) = 112903/4800 (Python 3.8 fractions from the legal definitions)

### 40 mpg (UK) in mpg (US)

- 값: 40 mpg (UK)
- 변환 전: mile per imperial gallon (mpg (UK))
- 변환 후: mile per US gallon (mpg (US))
- **변환된 값: 33.3069673852 mpg (US)**
- 검증 출처: 40 × 3.785411784 / 4.54609 (Python 3.8 fractions from the legal definitions)

### Crossover: 10 km/L equals 10 L/100 km

- 값: 10 km/L
- 변환 전: kilometre per litre (km/L)
- 변환 후: litre per 100 km (L/100 km)
- **변환된 값: 10 L/100 km**
- **정확성: 정확함**
- 검증 출처: 100 / 10 = 10 — the one value where km/L and L/100 km coincide

## 자주 묻는 질문

### How do I convert mpg to L/100 km?

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.

### Why is UK mpg higher than US mpg for the same car?

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.

### Why does going from 10 to 20 mpg save more fuel than 30 to 50 mpg?

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.

### How do I convert km/L to L/100 km?

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.

### Is a lower L/100 km better?

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.

### “연비 변환기 (mpg → L/100 km)”의 정확도는 어느 정도인가요?

정확도는 입력값과 계산 방법의 가정에 따라 달라집니다. 십진 연산은 유효숫자 50자리를 사용하지만, 추정값·수치해석 방법·원본 데이터의 정밀도는 더 낮을 수 있습니다. 표시값을 반올림해도 이러한 한계는 사라지지 않습니다. 독립적인 출처의 풀이와 대조한 계산 예시: 4. 예를 들어 “30 mpg (US) in L/100 km”은 100 ÷ (30 × 1.609344 km / 3.785411784 L) = 112903/14400 (Python 3.8 fractions from the legal definitions)와 대조해 확인합니다.

### 이 계산 방법의 출처는 무엇인가요?

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.

## 출처

- [NIST SP 811 (2008), Guide for the Use of the SI, Appendix B — conversion factors](https://www.nist.gov/pml/special-publication-811)
- [NIST Handbook 44, Appendix C — General tables of units of measurement](https://www.nist.gov/pml/owm/nist-handbook-44-current-edition)