BTU to Ton & Ton to BTU Converter

How to Convert Tons to BTUs (and vice versa)

When shopping for an air conditioner or a mini-split system, you will frequently see cooling capacity measured in either Tons or BTUs (British Thermal Units). Understanding how to convert between the two is simple once you know the golden rule of HVAC sizing:

To convert Tons to BTUs, multiply the tonnage by 12,000.
Example: A 2-Ton AC unit produces 24,000 BTUs of cooling power (2 × 12,000).

To convert BTUs to Tons, divide the BTUs by 12,000.
Example: An 18,000 BTU mini-split is a 1.5-Ton system (18,000 ÷ 12,000).

Quick Conversion Chart

Here is a handy reference chart for the most common residential air conditioner sizes:

How Many BTU Are in a Ton of Cooling?

Every conversion on this page comes down to one number: 1 ton of air conditioning equals exactly 12,000 BTU per hour. Not roughly 12,000 — exactly. So the math never changes: multiply tons by 12,000 to get BTUs, or divide BTUs by 12,000 to get tons. Whether you're converting 18,000 BTU to tons or checking what a 3 ton unit actually puts out, it's the same simple division every single time.

BTU to Tons: Quick Answers for Common AC Sizes

These are the sizes people look up most, spelled out so you can skip the math. One heads-up before you scan the list: window units, portable ACs, and mini-splits come in sizes that don't land on clean half-ton steps — so if your conversion comes out to something like 0.83 tons, nothing is wrong with your unit. Central AC is where the neat half-ton sizes live.

5,000 BTU to Tons

5,000 BTU is about 0.42 tons(5,000 ÷ 12,000). This is the classic small window unit — right for a bedroom up to roughly 150 sq ft.

9,000 BTU to Tons

9,000 BTU is exactly 0.75 tons. You'll see this size constantly on mini-split heads — it's one of the most common single-room capacities.

10,000 BTU to Tons

10,000 BTU works out to about 0.83 tons. This is portable AC territory, though remember portable units are rated two ways — check whether the box says ASHRAE or SACC, because they differ a lot.

12,000 BTU to Tons

12,000 BTU is exactly 1 ton— the definition itself. A 12,000 BTU mini-split and a "1 ton unit" are the same thing wearing different labels.

15,000 BTU to Tons

15,000 BTU equals 1.25 tons. Common for large window units and mid-size portables meant for open living areas.

18,000 BTU to Tons

18,000 BTU is exactly 1.5 tons(18,000 ÷ 12,000 = 1.5). This is the most-searched conversion of them all, and no wonder — 1.5 ton systems are everywhere, from mini-splits to small central units covering roughly 600–900 sq ft.

24,000 BTU to Tons

24,000 BTU is exactly 2 tons. This is where central air conditioning sizes really begin — a typical fit for homes around 900–1,200 sq ft.

30,000 BTU to Tons

30,000 BTU equals 2.5 tons— a very common central AC size for homes in the 1,200–1,500 sq ft range.

36,000 BTU to Tons

36,000 BTU is exactly 3 tons— arguably the most common central AC size installed in American homes, typically serving 1,500–1,800 sq ft.

42,000 BTU to Tons

42,000 BTU works out to 3.5 tons, generally matched with homes around 1,800–2,100 sq ft.

48,000 BTU to Tons

48,000 BTU is exactly 4 tons— big-house territory, usually 2,100–2,400 sq ft depending on climate and insulation.

60,000 BTU to Tons

60,000 BTU equals 5 tons, the top of the standard residential range. If a load calculation says your home needs more than 5 tons, contractors usually quote two separate systems rather than one giant unit.

Tons to BTU: Every Common Size Spelled Out

Going the other direction — you know the tonnage and want BTUs — here's the whole residential lineup in one glance:

• 1 ton = 12,000 BTU/hr
• 1.5 tons = 18,000 BTU/hr — the most common size people convert
• 2 tons = 24,000 BTU/hr
• 2.5 tons = 30,000 BTU/hr
• 3 tons = 36,000 BTU/hr
• 3.5 tons = 42,000 BTU/hr
• 4 tons = 48,000 BTU/hr
• 5 tons = 60,000 BTU/hr

And if you're converting because you're sizing a new unit: knowing the BTUs is only half the job. Whether that capacity is right for your room is the question our AC Unit Tonnage Calculator answers — it factors in your climate zone, insulation, and sun exposure instead of guessing from square footage alone.

Frequently Asked Questions