BTU Calculator

ASHRAE-compliant room load calculator · No sign-up required

Manual J StandardFree · No Sign-up

1 · Select Room Type

2 · Room Size

Square Footage

500sq ft

100 sq ft3,000 sq ft

3 · Environment Factors

Sun Exposure

Insulation Quality

Estimated BTU Required

11,000BTU/hr

≈ 0.9 tons of cooling capacity

Quick Summary

Room TypeBedroom
Area500 sq ft
Sun ExposureSunny ☀️
InsulationAverage

Recommended AC Capacity

12,000 BTU

1.0 Ton Unit

Nearest standard size above your calculated 11,000 BTU/hr requirement.

Top-Rated Cooling Units for US Homes

Matched to your calculated BTU range. Vetted for reliability, efficiency, and real-world performance based on verified buyer reviews.

8KBTU

Budget Pick

hOmeLabs 8,000 BTU Window AC

4.3(12,455)

Cools up to 350 sq ft efficiently
3 fan speeds + built-in dehumidifier
24-hour programmable timer

Typical Price

$179 – $219

View on Amazon

12KBTU

Best Overall

Midea 12,000 BTU U-Shaped Window AC

4.6(8,432)

U-shape — window stays usable
CEER 15 energy-star certified
Alexa & Google Home compatible

Typical Price

$349 – $399

View on Amazon

18KBTU

Large Rooms

LG 18,000 BTU Dual Inverter Window AC

4.4(3,891)

Dual Inverter — 25% quieter operation
Up to 25% more efficient vs fixed-speed
SmartThinQ Wi-Fi app control

Typical Price

$549 – $629

View on Amazon

Prices shown are estimates. We may earn a commission from Amazon links at no extra cost to you.

Quick Reference

BTU Chart by Room Size

Use this table to quickly sanity-check your result, or look up the BTU needed for any space at a glance.

Room Size	BTU Required	Tonnage	Typical Use
100 – 150 sq ft	5,000 BTU	0.4 ton	Small bedroom
150 – 250 sq ft	6,000 BTU	0.5 ton	Master bedroom
250 – 400 sq ftBest Seller	8,000 BTU	0.7 ton	Studio / 1BR apt
400 – 550 sq ft	10,000 BTU	0.8 ton	Living room
550 – 700 sq ftMost Popular	12,000 BTU	1.0 ton	Open-plan room
700 – 1,000 sq ft	14,000 BTU	1.2 ton	Large open plan
1,000 – 1,400 sq ft	18,000 BTU	1.5 ton	Combined spaces
1,400 – 2,000 sq ft	24,000 BTU	2.0 ton	Whole floor
2,000 – 2,500 sq ft	30,000 BTU	2.5 ton	Large home zone

Based on ASHRAE Standard 183 guidelines. Assumes 8 ft ceilings, average insulation, and moderate sun exposure. Add 10% for kitchens; subtract 10% for heavily shaded rooms.