About this calculator

Rough rule: 600 BTU per m² for typical climates, +10% per sunny window, +600 per occupant beyond two. Multiply BTU/h by 0.000293 for kW.

Frequently asked questions

What does the Room BTU / AC Sizing Calculator do?

How many BTU/h of cooling or heating your room needs. Rough rule: 600 BTU per m² for typical climates, +10% per sunny window, +600 per occupant beyond two. Multiply BTU/h by 0.000293 for kW.

Is the Room BTU / AC 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 Room BTU / AC 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 hvac & climate professional before committing to a purchase or a job.

What inputs does the Room BTU / AC Sizing Calculator need?

Enter values for: Room area (m²), Sunny windows, Occupants, Room type. Sensible defaults are pre-filled where possible so you can start with a single change.

Can I embed the Room BTU / AC 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.