Understanding Flow Rate Conversions
Flow rate is a critical measurement in plumbing, irrigation, fire protection, and industrial processes. The Gallons Per Minute (GPM) is the standard Imperial unit used primarily in the United States, while Liters Per Minute (LPM) is the standard Metric unit used almost everywhere else.
The Conversion Principle
The conversion is based on the volume difference between a US gallon and a liter, as the "Per Minute" time component is the same. The widely accepted standard conversion is:
$$\mathbf{1 \text{ US Gallon} = 3.78541 \text{ Liters}}$$
Conversion Formulas
GPM to LPM
To convert GPM to LPM, you multiply the GPM value by the conversion factor: $$\mathbf{F_{\text{LPM}} = F_{\text{GPM}} \times 3.78541}$$
LPM to GPM
To convert LPM to GPM, you divide the LPM value by the conversion factor: $$\mathbf{F_{\text{GPM}} = \frac{F_{\text{LPM}}}{3.78541}}$$
Note on Gallon Types:
This calculator uses the **US Liquid Gallon**. If converting from the less common **Imperial Gallon** (used in the UK/Canada), the conversion factor is different ($\mathbf{1 \text{ Imperial Gallon} \approx 4.54609 \text{ Liters}}$).