The result gives a planning capacity and a nearby standard unit size.
Home & Construction calculator
Air Conditioner BTU Calculator
Get a practical BTU-per-hour range before confirming the final unit size with an installer.
Calculated privately on your device
No account. Formula and assumptions are shown below.
Calculator inputs
Air conditioner BTU details
Formula & disclaimer
Recommended BTU/h = ENERGY STAR Area Capacity Γ Ceiling Adjustment Γ Sun Adjustment + Occupancy and Kitchen Adjustments
View assumptionsFormula reviewCalcs at Hand Editorial TeamVerified 28 August 2026 Β· automated checks included
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Resultβ
Projection
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Formula & details
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How to read this result
Three useful checks, kept deliberately short.
A 25 mΒ² living room with a 2.6 m ceiling and two occupants: Convert the area to square feet Β· Read the base capacity from the sizing table Β· Apply the selected room adjustments.
Climate, insulation, glazing, floor level, appliance heat and layout can materially change the actual cooling load.
Formula and assumptions
Recommended BTU/h = ENERGY STAR Area Capacity Γ Ceiling Adjustment Γ Sun Adjustment + Occupancy and Kitchen AdjustmentsThe base sizing table is designed around rooms with an 8-foot ceiling, then this tool applies transparent planning adjustments.
Keep in mind: Use this as a first estimate only. Ask a qualified installer to assess the room and local climate before purchase.
Official sourcesENERGY STAR room air-conditioner sizing guide β
Produced byCalcs at Hand Editorial Team
Last formula check28 August 2026
Review methodKnown examples + boundary cases
Editorial and correction policy β