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Split AC Tonnage Calculator: Find the Right Size for Your Room

Enter your room dimensions, climate, and details below to find the right split AC tonnage. Split air conditioners are sized in tons, so we match your room's cooling load to the nearest standard capacity and show both tons and BTU.

Split AC Tonnage Calculator

Feet
InchesSwitch between feet and inches measurement units
This form calculates the optimal air conditioner size for your room based on dimensions, climate, and various factors.

Room Dimensions

Room Dimensions Input Fields
ft
ft
ft

Location & Room Type

Location and Room Type Selection

Room Characteristics

Room Characteristics

Environmental Factors

Environmental Factors

Heat-Generating Appliances

Heat-Generating Appliances

Recommended Split AC Size

Room Area:144.00 sq ft
Room Volume:1440.00 cubic ft
Room Cooling Load:6,667 BTU

Recommended Split AC Size

0.75 Ton

9,000 BTU (0.75 Ton)

What This Means

Based on your room's dimensions and conditions, we recommend a 9,000 BTU (0.75 Ton) split air conditioner. This size will cool your room while maintaining proper humidity levels. The calculation is based on your local climate conditions and applies a combined adjustment factor of 1.79x.

This calculator uses the same room cooling-load engine as our main AC tonnage calculator, then matches it to standard split air conditioner sizes. Inspired by ASHRAE standards and ACCA Manual J.

What Tonnage Split AC Do I Need?

To find the right split AC tonnage, calculate your room's cooling load (room square footage × 20–25 BTU, adjusted for climate, ceiling height, sun, and occupancy), divide by 12,000, and round to the nearest standard size: 0.75, 1, 1.25, 1.5, or 2 tons. A typical 250 sq ft room needs about a 1 ton (12,000 BTU) split AC.

Add half a ton if the room gets direct afternoon sun, has high ceilings, or regularly holds more than two people. Use the calculator above for a number tailored to your climate zone.

Split AC Tonnage by Room Size (Quick Reference)General split AC sizing at 20–25 BTU per sq ft. Enter your climate zone above for an exact recommendation.
Room Size (sq ft)Split AC TonnageCapacity (BTU)
Up to 150 sq ft0.75 Ton9,000 BTU
150 – 250 sq ft1 Ton12,000 BTU
250 – 400 sq ft1.25 – 1.5 Tons15,000 – 18,000 BTU
400 – 600 sq ft2 Tons24,000 BTU

How Split AC Sizing Works

A split air conditioner sizing starts with the same room cooling-load calculation used by our main AC tonnage calculator. We take your room's square footage, apply a baseline of about 22 BTU per square foot, then adjust for ceiling height, climate zone, sun exposure, insulation, occupants, and appliances.

Split systems are specified in tons, so we divide the calculated load by 12,000 and round to the nearest standard residential tonnage (the tons to BTU chart spells out every standard size). This is the closest match to our main calculator, which also reports tonnage.

Want the full formula? See our methodology page. For a ductless single-zone unit, use the mini split size calculator, or for a plug-in room unit try the window AC BTU calculator.

Frequently Asked Questions

How do I calculate split AC tonnage for a room?

Multiply the room's square footage by roughly 22 BTU per square foot, adjust for climate zone, ceiling height, sun exposure, and occupancy, then divide by 12,000 to get tons and round to the nearest standard size: 0.75, 1, 1.5, or 2 tons. The calculator above applies all of these adjustments for you and reports both tons and BTU.

How many square feet does a 1.5 ton split AC cover?

A 1.5 ton (18,000 BTU) split AC covers roughly 600-900 square feet in a moderate climate, or 500-700 square feet in hot and humid regions. It's the most common size for large living rooms and open living-dining areas. If your space has high ceilings or heavy afternoon sun, expect the lower end of the range.

Is a 1 ton split AC enough for a 12x12 bedroom?

A 12x12 bedroom (144 sq ft) only needs about 0.5-0.75 tons, so a 1 ton unit is actually more than enough. For a non-inverter AC, stick close to 0.75 tons to avoid short cycling and poor humidity removal. For an inverter AC, 1 ton is fine because the compressor slows down instead of switching off once the room reaches temperature.

What is the difference between a split AC and a mini split?

They're the same technology - an outdoor compressor connected to an indoor unit by refrigerant lines, with no ductwork. 'Split AC' is the common term in Asia and the Middle East where wall-mounted units are sized in tons, while 'ductless mini split' is the North American term where units are sized in BTU. Our split calculator reports tons; the mini split calculator reports BTU sizes.

Should I choose an inverter or non-inverter split AC?

An inverter split AC varies its compressor speed to match the room's load, which gives better humidity control, quieter operation, and 20-40% lower running costs - and it tolerates slight oversizing. A non-inverter unit only runs at full blast, so sizing must be precise to prevent short cycling. If the price difference is manageable, the inverter is nearly always the better long-term buy.

What size split AC do I need for a kitchen or living room?

Add capacity beyond the square-footage math. Kitchens generate roughly 4,000 extra BTU from appliances, so a 150 sq ft kitchen that would calculate at 0.5 tons really needs about 1 ton. Living rooms add around 1,000 BTU for foot traffic and open-plan spillover. Select the room type in the calculator above and it applies these adjustments automatically.