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BTU Calculator
Calculate how many BTUs you need to cool or heat a room. Find the right AC or heater size based on room dimensions and climate.
Watts
US average: $0.13/kWh · UK: ~$0.28 · Australia: ~$0.25
Daily kWh12 kWh
Monthly kWh360 kWh
Cost Per Day$1.56
Cost Per Month$46.80
Cost Per Year$569.40
How to Use the BTU Calculator
Enter your values above for an instant result. This tool uses verified formulas and is optimised for users in USA, Canada, UK, Australia. All calculations happen in your browser — your data is never sent to our servers.
Frequently Asked Questions
How many BTUs do I need for a 1000 sq ft room?
A general rule is 20 BTUs per square foot. A 1,000 sq ft room needs approximately 20,000 BTUs, adjusted for ceiling height and insulation.