# 流量转换器

> 使用美制加仑与立方英尺的精确值，为水泵、管道和通风换算L/min到gpm、gpm到L/min、cfm到m³/h及m³/h到L/s。

交互版本：https://www.calcopenly.com/zh/conversion/flow-rate-converter
主题：单位换算器

Flow rate is volume per time, and each unit here is a fixed number of cubic metres per second. The US gallon (3.785411784 L) and the cubic foot (28.316846592 L) are exact, so litres per minute, gallons per minute and cubic feet per minute convert with no rounding in the factors.

The default converts 10 L/min to 2.64 US gpm, close to the 2.5 gpm (9.46 L/min) of a standard US showerhead. Plumbers and pump buyers use L/min and gpm, fan and compressor ratings use cfm or m³/h, and river flows are reported in m³/s (cumecs).

The gallon here is the US gallon. An imperial gallon per minute is 4.54609 L/min, 20% more, so check which gallon a specification uses before converting it.

## 输入

- **数值**: 输入源单位下的数值，也可以输入带有自身单位的数值
- **从** (选项：cubic metre per second (m³/s), cubic metre per hour (m³/h), litre per second (L/s), litre per minute (L/min), litre per hour (L/h), US gallon per minute (gal/min), cubic foot per minute (ft³/min))
- **到** (选项：cubic metre per second (m³/s), cubic metre per hour (m³/h), litre per second (L/s), litre per minute (L/min), litre per hour (L/h), US gallon per minute (gal/min), cubic foot per minute (ft³/min))

## 结果

- 转换后的数值 — 主要结果
- 换算
- 换算系数
- 精确性

## 公式

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

## 计算示例

### 10 L/min in US gal/min

- 数值: 10 L/min
- 从: litre per minute (L/min)
- 到: US gallon per minute (gal/min)
- **转换后的数值: 2.6417205236 gal/min**
- 核验来源：10 L ÷ 3.785411784 L = 1250000000/473176473 (Python 3.8 fractions from the legal definitions)

### 1 m³/s in L/s

- 数值: 1 m³/s
- 从: cubic metre per second (m³/s)
- 到: litre per second (L/s)
- **转换后的数值: 1,000 L/s**
- 核验来源：1 m³ = 1000 L

### 1 cfm in L/min

- 数值: 1 ft³/min
- 从: cubic foot per minute (ft³/min)
- 到: litre per minute (L/min)
- **转换后的数值: 28.316846592 L/min**
- 核验来源：1 ft³ = 0.3048³ m³ = 28.316846592 L (NIST HB 44 App. C)

### 1 m³/h in L/s

- 数值: 1 m³/h
- 从: cubic metre per hour (m³/h)
- 到: litre per second (L/s)
- **转换后的数值: 0.2777777778 L/s**
- **精确性: 定义精确，结果为循环小数**
- 核验来源：1000 L / 3600 s = 5/18

## 常见问题

### How do I convert L/min to gpm?

Divide by 3.785411784, or multiply by 0.264172. 10 L/min is 2.64 US gpm and 20 L/min is 5.28 gpm. To go from US gpm to L/min, multiply by 3.785, so a 2.5 gpm showerhead runs at 9.46 L/min.

### How do I convert cfm to m³/h?

Multiply by 1.69901. A cubic foot is 0.028316846592 m³ and an hour is 60 minutes, so 1 cfm = 1.69901079552 m³/h exactly. A 100 cfm bathroom fan moves 169.9 m³/h, or 47.2 L/s. To go from m³/h to cfm, multiply by 0.588578.

### What is a normal shower flow rate?

The US EPA puts standard showerheads at 2.5 gallons per minute, 9.46 L/min, and requires WaterSense-labelled ones to use no more than 2.0 gpm, 7.57 L/min. A 10-minute shower at 2.5 gpm uses 25 gallons, or 94.6 litres. Timing how long your shower takes to fill a 1-litre jug gives your own figure: 6 seconds means 10 L/min.

### How do I convert m³/h to L/s?

Divide by 3.6. A cubic metre is 1,000 litres and an hour 3,600 seconds, so 1 m³/h = 1,000/3,600 = 0.2778 L/s, a repeating decimal. A pump rated at 36 m³/h delivers exactly 10 L/s, or 600 L/min.

### Is gpm in US or imperial gallons?

In this converter, US gallons: 1 gpm = 3.785411784 L/min. Imperial gallons per minute are 4.54609 L/min, 20% larger, and appear on equipment specified in imperial units. To convert an imperial figure, multiply it by 1.20095 to get US gpm before entering it.

### “流量转换器”有多准确？

准确性取决于输入值和方法的假设。十进制运算使用50位有效数字，但估算、数值方法和源数据的精度可能较低；显示时的舍入并不能消除这些限制。 已按独立来源核验的计算示例：4。 例如，“10 L/min in US gal/min”根据10 L ÷ 3.785411784 L = 1250000000/473176473 (Python 3.8 fractions from the legal definitions)进行核验。

### 这种方法出自哪里？

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.

## 来源

- [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)