BTU to Gallons Per Hour Calculator

Convert BTU per hour into gallons per hour for water heater recovery, hot water production, and heating capacity. Estimate GPH, GPM, temperature rise, kW, therms, and how many gallons of water can be heated per hour.

Calculate BTU to Gallons Per Hour

Gallons Per Hour = BTU/hr × Efficiency ÷ (8.34 × Temperature Rise).
Your result will appear here.

How the BTU to GPH calculator works

BTU/hr to GPH:
The calculator converts heating input into gallons per hour using temperature rise and efficiency.

GPH to BTU/hr:
The calculator estimates how much BTU/hr is needed to produce a target gallons per hour recovery rate.

kW to GPH:
The calculator converts electric kW into BTU/hr, then estimates water heater recovery rate.

Recovery time:
The calculator estimates how long it takes to heat a selected amount of water.

Why use a BTU to gallons per hour calculator?

A BTU to gallons per hour calculator helps estimate water heater recovery and hot water production from heating capacity.

It can help compare BTU/hr, kW, temperature rise, efficiency, GPH, GPM, and tank recovery time.

What your result means

Your result shows estimated gallons per hour recovery from the entered BTU/hr, kW, temperature rise, and efficiency. This is a planning estimate only. Actual water heater performance should be checked against the manufacturer’s recovery rating, fuel type, burner input, element size, thermostat setting, and incoming water temperature.

BTU to gallons per hour formulas

Frequently asked questions

How do you convert BTU to gallons per hour?

Multiply BTU/hr by heater efficiency, then divide by 8.34 times the temperature rise.

Why does temperature rise matter?

Temperature rise is how much the water must be heated. A larger temperature rise lowers the number of gallons per hour a heater can recover.

What does GPH mean for a water heater?

GPH means gallons per hour. For water heaters, it usually describes how many gallons can be heated to the target temperature in one hour.

Is this BTU to GPH calculator exact?

No. This calculator gives a planning estimate. Actual recovery depends on heater design, efficiency, inlet water temperature, fuel type, and manufacturer ratings.