Gallons per minute (gal/min) to Litres per second (l/s) conversion

Understanding Gallons per minute to Litres per second Conversion

Gallons per minute ($gal/min$) and litres per second ($l/s$) are both units of volumetric flow rate, which describes how much liquid passes through a system in a given amount of time. Gallons per minute is commonly used in U.S. plumbing, pumps, irrigation, and industrial equipment, while litres per second is widely used in metric engineering, water treatment, and scientific contexts.

Converting from $gal/min$ to $l/s$ is useful when comparing specifications from different countries, interpreting equipment ratings, or working across systems that use U.S. customary and metric units. It helps standardize flow measurements for clearer design, reporting, and performance analysis.

Conversion Formula

To convert gallons per minute to litres per second, use the conversion factor:

$$1 \text{ gal/min} = 0.06309019640344 \text{ l/s}$$

So the conversion formula is:

$$\text{l/s} = \text{gal/min} \times 0.06309019640344$$

The reverse relationship is:

$$1 \text{ l/s} = 15.850323140625 \text{ gal/min}$$

Which can also be written as:

$$\text{gal/min} = \text{l/s} \times 15.850323140625$$

Step-by-Step Example

Suppose a pump delivers $48 \text{ gal/min}$ and the flow rate is needed in litres per second.

1. Write the formula

$$\text{l/s} = \text{gal/min} \times 0.06309019640344$$

2. Substitute the value

$$\text{l/s} = 48 \times 0.06309019640344$$

3. Calculate

$$48 \text{ gal/min} = 3.02832942736512 \text{ l/s}$$

So, a flow of $48 \text{ gal/min}$ is equal to $3.02832942736512 \text{ l/s}$.

Real-World Examples

• A residential booster pump rated at $25 \text{ gal/min}$ has a metric flow rate of $1.577254910086 \text{ l/s}$.
• A fire protection water line delivering $100 \text{ gal/min}$ corresponds to $6.309019640344 \text{ l/s}$.
• An irrigation zone flowing at $60 \text{ gal/min}$ is equal to $3.7854117842064 \text{ l/s}$.
• A small industrial process line operating at $150 \text{ gal/min}$ converts to $9.463529460516 \text{ l/s}$.

Interesting Facts

• The litre is a metric unit of volume equal to one cubic decimetre, and litres per second is commonly used in engineering for expressing water and fluid flow. Source: Wikipedia: Litre
• Gallons per minute is widely used in the United States for pump performance, plumbing flow, and well output, reflecting the continued use of U.S. customary units in many infrastructure applications. Source: NIST - SI and U.S. customary units

Additional Notes on Usage

Gallons per minute is often abbreviated as $GPM$, especially in pump curves, plumbing charts, and equipment manuals. Litres per second may appear as $L/s$ or $l/s$, depending on style guidelines, though the meaning is the same in flow-rate contexts.

Because these units measure volume per unit time, the conversion affects both the volume component and the time basis implicitly. In this case, the source and target units both express flow over time, but one uses gallons and minutes while the other uses litres and seconds.

This conversion is especially common in:

• water distribution engineering
• HVAC hydronic systems
• irrigation design
• filtration systems
• industrial pumping applications

When reading specification sheets, it is important to confirm which gallon definition is being used. On pages using the verified relationship above, the conversion is based exactly on:

$$1 \text{ gal/min} = 0.06309019640344 \text{ l/s}$$

For quick reference:

$$\text{l/s} = \text{gal/min} \times 0.06309019640344$$

And for converting back:

$$\text{gal/min} = \text{l/s} \times 15.850323140625$$

These formulas provide a direct way to move between U.S. customary and metric flow-rate values in technical and practical applications.

How to Convert Gallons per minute to Litres per second

To convert Gallons per minute (gal/min) to Litres per second (l/s), multiply the flow rate by the conversion factor between the two units. For this example, use the factor $1\ \text{gal/min} = 0.06309019640344\ \text{l/s}$.

1. Write the given value: Start with the flow rate in Gallons per minute.

   $$25\ \text{gal/min}$$

2. Use the conversion factor: Apply the factor that converts Gallons per minute directly to Litres per second.

   $$1\ \text{gal/min} = 0.06309019640344\ \text{l/s}$$

3. Set up the multiplication: Multiply the given value by the conversion factor.

   $$25\ \text{gal/min} \times 0.06309019640344\ \frac{\text{l/s}}{\text{gal/min}}$$

4. Calculate the result: The $\text{gal/min}$ units cancel, leaving Litres per second.

   $$25 \times 0.06309019640344 = 1.577254910086$$

5. Result:

   $$25\ \text{Gallons per minute} = 1.577254910086\ \text{Litres per second}$$

A quick check is to make sure the result is smaller than the gallons-per-minute value, since this conversion changes both volume and time units. Keeping the unit factor written as a fraction helps you cancel units correctly every time.

What is the formula to convert Gallons per minute to Litres per second?

To convert Gallons per minute to Litres per second, multiply the flow rate in gal/min by the factor $0.06309019640344$. The formula is: $l/s = gal/min \times 0.06309019640344$.

How many Litres per second are in 1 Gallon per minute?

There are exactly $0.06309019640344$ Litres per second in $1$ Gallon per minute. This value uses the conversion factor for gal/min to l/s.

Why would I convert Gallons per minute to Litres per second?

This conversion is useful when comparing flow rates between systems that use U.S. customary units and metric units. It is common in plumbing, pump sizing, irrigation, water treatment, and industrial fluid handling.

How do I convert a larger flow rate from Gallons per minute to Litres per second?

Use the same formula for any value: multiply the number of gal/min by $0.06309019640344$. For example, if a device is rated in gal/min, converting it to l/s makes it easier to compare with metric equipment specifications.

Is Gallons per minute a volume flow rate unit?

Yes, Gallons per minute measures volumetric flow rate, meaning how much volume passes a point each minute. Litres per second measures the same quantity, so the conversion only changes the unit, not the physical meaning.

Can I use this conversion for real-world water flow measurements?

Yes, this conversion is commonly used for real-world measurements such as faucet flow, pipe discharge, pump output, and filtration systems. Converting from gal/min to l/s helps when working with international standards, engineering documents, or metric-based equipment.