GPM to L/s Converter

Convert US gallons per minute (GPM) to litres per second (L/s). One US gallon is 3.785411784 litres and a minute is 60 seconds, so 1 GPM = 0.0630902 L/s. This is the conversion you need when a US pump or fixture rating has to be checked against an SI specification, where L/s is the standard unit for water supply and hydronic design.

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GPM to L/s conversion result

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How It Works

GPM is the unit on US pump curves, fixture ratings and irrigation equipment. L/s is the SI flow unit used in building services, water supply design and most metric standards. Both measure volume per unit of time, so the conversion needs no pipe size, pressure or fluid property: divide the gallon-to-litre factor by 60 and multiply.

GPM to L/s Formula

L/s = GPM × 0.0630902

One US gallon per minute equals 0.0630902 litres per second. Going the other way, one litre per second equals 15.8503 US gallons per minute.

Worked Example

Converting 100 GPM:

100 × 0.0630902 = 6.30902 L/s

GPM to L/s Conversion Table

GPM L/s
1 GPM 0.0630902 L/s
5 GPM 0.315451 L/s
10 GPM 0.630902 L/s
25 GPM 1.57725 L/s
50 GPM 3.15451 L/s
100 GPM 6.30902 L/s
250 GPM 15.7725 L/s
500 GPM 31.5451 L/s
1000 GPM 63.0902 L/s

Going the other way? Use the L/s to GPM converter. For any other unit pair, the full flow rate converter handles every supported unit.

FAQ

Common questions about converting US gallons per minute to litres per second.

Frequently Asked Questions

How do I convert GPM to L/s?

Multiply the GPM value by 0.0630902. For example, 100 GPM x 0.0630902 = 6.30902 L/s. The factor is 3.785411784 litres per US gallon divided by 60 seconds per minute.

How many litres per second is 1 GPM?

One US gallon per minute is 0.0630902 litres per second, or about 63 millilitres per second. A tap running at 2 GPM delivers roughly 0.126 L/s.

What is 100 GPM in L/s?

100 GPM is 6.30902 L/s. For a quick estimate, divide GPM by 16: 100 / 16 = 6.25 L/s, within 1% of the exact answer.

Why is L/s used instead of L/min?

L/s is the SI-coherent unit, so it drops straight into formulas written in metres and seconds (velocity = Q/A with Q in m³/s, which is L/s divided by 1000). Water supply and building services standards outside the US are written in L/s; L/min is more common on domestic fixtures and small pumps.

Is this US GPM or Imperial GPM?

US gallons (3.78541 L). An Imperial gallon is 4.54609 L, so 1 Imperial GPM = 0.0757682 L/s, about 20% more. Check which gallon a UK or Canadian specification means before converting.

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