Ever needed to compare a garden‑irrigation pump’s output with a laboratory’s fluid‑dispensing system? Both talk about how fast liquid moves, but they use different units. Converting gallons per hour (gal/h) to quarts per second (qt/s) clears the confusion and lets you make informed decisions quickly.

Exact conversion factor: 1 gal/h = 0.001111 qt/s = 1⁄900 qt/s.

Understanding Volume Flow Rate

Volume flow rate measures how much space a fluid occupies as it moves through a pipe or channel per unit of time. It’s the “speed” of a liquid expressed in volume units, not distance.

What Is a Gallon Per Hour (gal/h)?

A gallon per hour tells you how many US liquid gallons pass a point in one hour. One US gallon equals 4 quarts, 128 fluid ounces, or about 3.785 liters.

What Is a Quart Per Second (qt/s)?

A quart per second indicates the number of US liquid quarts flowing each second. Since a quart is one‑quarter of a gallon, this unit is useful for high‑speed applications where “per hour” feels too slow.

How the Two Units Relate

Both units belong to the same measure—volume flow rate—so they share the same physical meaning. The only difference is the time base (hour vs. second) and the volume base (gallon vs. quart).

Because 1 gallon = 4 quarts and 1 hour = 3,600 seconds, the relationship is:

• Convert gallons to quarts: multiply by 4.
• Convert hours to seconds: divide by 3,600.

Combining the steps gives the single factor 1 gal/h = 4 ÷ 3,600 qt/s = 1⁄900 qt/s.

Step‑by‑Step Conversion Formula

To turn any value in gallons per hour into quarts per second, use the formula:

qt/s = (gal/h) × 4 ÷ 3,600

Or, simplified:

qt/s = (gal/h) ÷ 900

Worked Example: Converting 15 gal/h to qt/s

1. Start with the source value: 15 gal/h.
2. Divide by 900 (the conversion factor): 15 ÷ 900 = 0.016666…
3. Round to a practical precision (four significant figures): 0.01667 qt/s.

So a pump delivering 15 gal/h moves roughly 0.0167 qt each second.

Practical Applications

• Plumbing design: Size pipes for residential water heaters that are rated in gal/h while the flow sensor reads qt/s.
• Agriculture: Match irrigation schedules (gal/h) with drip‑line controllers that operate in qt/s.
• Industrial processes: Translate equipment specifications from US customary units to metric‑friendly flow meters that often use seconds as the time base.
• Laboratory work: Convert reagent delivery rates for precise dosing when the pump’s manual lists gal/h.

Gallon Per Hour to Quart Per Second Conversion Table

Each row applies the same rule: multiply gallons per hour by 1⁄900 (or divide by 900) to obtain quarts per second.

Key Takeaways

The conversion between these two common flow‑rate units is straightforward: divide the gal/h value by 900. Knowing this factor lets you compare equipment, size piping, and troubleshoot systems without hunting for a calculator.

Ready to apply the conversion to your own project? Plug your numbers into the formula or grab a row from the table and see instant results.