# 밀도 변환기

> Convert g/cm³ to kg/m³, kg/m³ to lb/ft³ and lb/gal (ppg), and g/mL to kg/L, with exact factors from the 1959 pound and foot.

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

Density is mass per volume, so each unit is a mass unit divided by a volume unit, held here as kilograms per cubic metre. The metric units differ by powers of 1,000 (1 g/cm³ = 1 g/mL = 1 kg/L = 1,000 kg/m³), and the imperial ones follow from the exact pound and foot: 1 lb/ft³ = 16.0185 kg/m³.

The default converts 1 g/cm³, close to the density of water, to 62.428 lb/ft³. Engineers use lb/ft³ (pcf) for soils and concrete, drillers use lb/gal (ppg) for drilling mud, and materials data sheets use g/cm³.

Density changes with temperature, and the converter only changes units. Pure water is densest near 4 °C at 999.97 kg/m³ and is 998.2 kg/m³ at 20 °C, so “1 g/cm³ for water” is right to within 0.2%.

## 입력

- **값**: 변환 전 단위의 숫자 또는 단위가 붙은 숫자를 입력하세요
- **변환 전** (선택 항목: kilogram per cubic metre (kg/m³), gram per cubic centimetre (g/cm³), gram per millilitre (g/mL), kilogram per litre (kg/L), pound per cubic foot (lb/ft³), pound per cubic inch (lb/in³), pound per US gallon (lb/gal))
- **변환 후** (선택 항목: kilogram per cubic metre (kg/m³), gram per cubic centimetre (g/cm³), gram per millilitre (g/mL), kilogram per litre (kg/L), pound per cubic foot (lb/ft³), pound per cubic inch (lb/in³), pound per US gallon (lb/gal))

## 결과

- 변환된 값 — 주요 결과
- 단위 변환
- 변환 계수
- 정확성

## 공식

$$
\begin{gathered} x_{\text{to}} = x_{\text{from}} \times \dfrac{f_{\text{from}}}{f_{\text{to}}} \\ f = \text{one unit expressed in } \text{kg/m³} \end{gathered}
$$

## 계산 예제

### 1 g/cm³ in lb/ft³

- 값: 1 g/cm³
- 변환 전: gram per cubic centimetre (g/cm³)
- 변환 후: pound per cubic foot (lb/ft³)
- **변환된 값: 62.4279605761 lb/ft³**
- 검증 출처: 1000 kg/m³ ÷ (0.45359237 kg / 0.028316846592 m³) = 14158423296/226796185 (Python 3.8 fractions from the legal definitions)

### 1000 kg/m³ in g/mL

- 값: 1000 kg/m³
- 변환 전: kilogram per cubic metre (kg/m³)
- 변환 후: gram per millilitre (g/mL)
- **변환된 값: 1 g/mL**
- 검증 출처: 1000 kg/m³ = 1 g/cm³ = 1 g/mL

### 1 lb/gal in kg/m³

- 값: 1 lb/gal
- 변환 전: pound per US gallon (lb/gal)
- 변환 후: kilogram per cubic metre (kg/m³)
- **변환된 값: 119.826427317 kg/m³**
- 검증 출처: 0.45359237 / 0.003785411784 (Python 3.8 fractions from the legal definitions)

### 1 lb/in³ in g/cm³

- 값: 1 lb/in³
- 변환 전: pound per cubic inch (lb/in³)
- 변환 후: gram per cubic centimetre (g/cm³)
- **변환된 값: 27.6799047102 g/cm³**
- 검증 출처: 0.45359237 kg / 0.000016387064 m³ ÷ 1000 (Python 3.8 fractions from the legal definitions)

## 자주 묻는 질문

### How do I convert g/cm³ to kg/m³?

Multiply by 1,000. A cubic metre holds 10⁶ cubic centimetres and a kilogram is 1,000 grams, so 1 g/cm³ = 1,000 kg/m³. Aluminium at 2.70 g/cm³ is 2,700 kg/m³, and steel at about 7.85 g/cm³ is 7,850 kg/m³. g/mL and kg/L are the same size as g/cm³.

### What is specific gravity?

The ratio of a substance's density to the density of water, so it has no unit. Referenced to water at 4 °C (999.97 kg/m³), specific gravity equals the density in g/cm³ to within 0.003%: a liquid of 0.80 g/cm³ has a specific gravity of 0.80. Other references, such as water at 60 °F, change the fourth significant digit.

### How do I convert lb/ft³ to kg/m³?

Multiply by 16.0185. A pound is 0.45359237 kg and a cubic foot 0.028316846592 m³, both exact, so 1 lb/ft³ = 16.01846337 kg/m³. Normal-weight concrete at about 150 lb/ft³ is about 2,400 kg/m³, and 1,000 kg/m³ is 62.43 lb/ft³.

### What does ppg mean for drilling mud?

Pounds per US gallon, the density unit of oilfield drilling fluids. 1 lb/gal is 119.826 kg/m³, so fresh water at 20 °C is 8.33 ppg and a 12 ppg mud is 1,438 kg/m³, or 1.44 g/cm³. Mud weight sets the pressure the fluid column exerts at the bottom of the well.

### Is the density of water exactly 1 g/cm³?

No, but close. Pure water peaks at 999.97 kg/m³ near 4 °C and is 998.2 kg/m³ at 20 °C. The gram was first defined in 1795 as the mass of 1 cm³ of water, and from 1901 to 1964 the litre was defined as the volume of 1 kg of water, which is why the numbers nearly coincide.

### “밀도 변환기”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 “1 g/cm³ in lb/ft³”은 1000 kg/m³ ÷ (0.45359237 kg / 0.028316846592 m³) = 14158423296/226796185 (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)