Air Conditioner Size Calculator – Steps to find AC Tonnage with online Calculator

Saad Iqbal | 🗓️Modified: May 6, 2022 | ⏳Time to read:5 min

Looking to find the right AC tonnage for you room; this online air conditioner size calculator will make your choice simple. This AC tonnage calculator helps you easily figure out the size depending on factors like number of persons, maximum temperature, and size of room.

AC Tonnage Calculator

There are many factors that can impact how much cooling capacity you’ll need to get your home feeling comfortable. Below, we’ll explore the factors that affect how much cooling capacity you need, and we’ll walk you through using our air conditioner size calculator to determine the perfect fit for your home.

There are a few different sizes of air conditioners available, depending on your home’s needs and budget. In order to choose the best one, consider these three steps to calculating your AC tonnage.

The most common type is window AC unit and split system AC. Window AC units are available in different sizes: 6, 7, 8 and 10 tons while split system can range from 2 to 5 tons.

Here’s the calculator:

Steps for finding right AC tonnage with online calculator

Find your room size or calculate the room size to determine the tonnage of air conditioner. The first step in deciding which air conditioner you need is to find the size of your room or room area in square feet and then use an AC tonnage calculator, such as this one, to figure out what size of air conditioner you need based on factors like number of persons in the room, humidity levels, and maximum temperature in Celsius.

Using an air conditioner size calculator can help you choose the right size of air conditioner for your home or room. This step-by-step guide will show you how to choose the right size of air conditioner based on the number of people in the room, room size, and maximum temperature in your home.

Air Conditioner size Calculator online
Air Conditioner size Calculator online

Before you settle on a size and brand, calculate your room’s heat load. This will help you decide how many tons of AC you need. Measure your living room from floor to ceiling and add 20%. If there are windows, measure them as well. The length of your room is its footprint in square feet (the length times width). Divide that by 144 if you’re using metric (multiply length by width) and then divide that number by 12 for a rough estimate (floor area divided by 12 = BTU’s per hour) or multiply it by .0023751 if using English units.



Sr. Square
1 100 – 200 1.0 30 – 60 1.0
2 200 – 400 1.5 60-120 1.5
3 400 – 500 2.0 120 – 150 2.0
4 500 – 700 2.5 150 – 210 2.5
5 700 – 900 3.0 210 – 275 3.0


What is AC tonnage means?

Well, you may confuse AC tonnage with the weight. However, there’s no relationship between weight and tons of AC. A ton is in fact a AC unit cooling capacity most HVAC experts use to express the amount of heat an AC unit can remove from a home in one hour. We measure the heat in BTU or British Thermal Unit. So, if you have a 1 ton AC that means it can remove 12,000 BTUs or 288,000 BTU’s per 24 hours.

So, if someone asks you about what size of AC you’re using in for a particular room. It doesn’t mean they’re asking for a physical dimension but in contrast they’re asking for the cooling capacity.

If you already have an AC in your home and want to don’t know how to find the tonnage of your AC unit, here’s a trick:

In most of the cases the manufacturer displays the tonnage of AC on the label on the condenser unit. But on the other day’s you’re not always lucky. So, if you can figure out the BTUs of your HVAC system you can easily calculate the tonnage of your AC. Simply divide the BTUs by 12,000 to get tons.

Sr. BTU Ac
1 9,000 3/4 Ton
2 12,000 1 Ton
3 24,000 2 Ton
4 36,000 3 Ton
5 48,000 4 Ton


Air Conditioning British Thermal Units (AC BTUs)?

The British Thermal Unit (BTU) is a unit of heat energy that tells us The quantity of heat required to raise one pound (0.454 kg) or one cubic foot (0.02832 m) or one degree Fahrenheit (1°F) in temperature at one atmosphere pressure.

In another words, BTU describes a quantity of heat that it takes to increase one pound in temperature by 1 degree Fahrenheit. It’s also often expressed as MBTU, which stands for Million British Thermal Units.

It only takes 0.2931MBTUs or 1/100th of a BTU to increase the temperature on one pound by 1°F.


Saad Iqbal is a professional civil engineering and freelance write. He's passionate about structures, construction management, and home improvement topics. He's been working as a Senior Engineer in a consultant firm for over 8 years. Besides he loves writing informative and in-depth content focused on construction and home-related topics. You can catch him at his linkedin page or reach out via our contact us page.

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