BTU Calculator
When you need to check bTU, the BTU gives you a clear starting point. Enter one realistic example first, then compare another option if useful.
Recommended cooling capacity
—
In kilowatts —
Typical unit size —
✉ Email me this result
</> Embed this calculator
Paste this into any website or blog post. It is free — the small "powered by" link must stay visible.
How it works
BTU ≈ area × 20, adjusted for sun exposure, insulation and extra occupantsHow to use the BTU
Enter the requested values and start with one realistic example. Read the result together with its unit or label, then change one input at a time if you want to compare options.
Allow for waste, packaging, site conditions and local requirements before buying materials.
Frequently Asked Questions
How many BTU do I need per square foot?
Roughly 20 BTU per sq ft for cooling: a 300 sq ft bedroom needs about 6,000 BTU, a 500 sq ft living room about 10,000–12,000 once sun and people are factored in.
What happens if my AC is oversized?
It short-cycles: cooling fast but shutting off before dehumidifying, leaving the room cold and clammy while wearing out the compressor. Right-sized beats bigger.
Do kitchens need extra BTU?
Yes — add about 4,000 BTU for a kitchen's appliance heat, and about 600 BTU for each person beyond two regularly in the room. The calculator applies the occupant adjustment.