Heating tool
Pool Heater Sizing Calculator
Estimate heat-up capacity from gallons, desired temperature rise and target heat-up time.
Estimated heater output: —
Planning formula
Water weighs about 8.34 lb per gallon and requires about 1 BTU to raise 1 lb by 1°F. Baseline BTU/hr = gallons × 8.34 × temperature rise ÷ hours. This tool adds a 20% planning margin, but real heat loss from air temperature, wind and evaporation can materially increase required capacity.