About this calculator

BTU = volume (gal) × 8.34 × temp rise (°F) ÷ hours. Add ~20% for heat loss in open pools, more for chilly nights.

Frequently asked questions

What does the Pool Heater Sizing Calculator do?

BTU heater output to raise pool temperature within X hours. BTU = volume (gal) × 8.34 × temp rise (°F) ÷ hours. Add ~20% for heat loss in open pools, more for chilly nights.

Is the Pool Heater Sizing Calculator free to use?

Yes. Every calculator on Calcurly.com is free, works in your browser without sign-up, and can be embedded on your own website.

How accurate is the Pool Heater Sizing Calculator?

Results are calculated in real time using industry-standard formulas. Treat the output as a well-informed estimate — always cross-check with local regulations, product datasheets, or a qualified swimming pool professional before committing to a purchase or a job.

What inputs does the Pool Heater Sizing Calculator need?

Enter values for: Pool volume (m³), Temp rise (°C), Time to heat (h). Sensible defaults are pre-filled where possible so you can start with a single change.

Can I embed the Pool Heater Sizing Calculator on my own website?

Yes — copy the iframe snippet at the bottom of this page, or use the Embed Generator to customise the size. The embedded version stays in sync with the live calculator on Calcurly.com.