Mini Split Sizing Calculator

Find the right size mini-split for a room or area.

UNIT TO BUY
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nearest mini-split

Usage Tip

Mini-splits are available in 9K, 12K, 18K, 24K, and 36K BTU sizes. Size up in cold climates.

THE MATH
BTU = Area × factor × (H ÷ 8)
Where: factor = 20/25/30/35 by climate  •  H = ceiling height
• Tons = BTU ÷ 12,000
• Mini-splits come in 9k, 12k, 18k, 24k, 36k BTU
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The calculators and tools on Formula Factory are provided for general guidance and informational purposes only. Results are estimates based on standard formulas and the values you enter — they do not constitute professional engineering, electrical, or architectural advice. Always verify calculations with a qualified professional before making decisions for any safety-critical, code-compliance, or commercial application. Formula Factory makes no representations or warranties as to the accuracy or completeness of any result, and accepts no liability for errors, omissions, or any outcomes arising from reliance on this information.