Air Compressor Sizing Calculator (CFM and HP)
- Sullair dealer since 1984
- Serving industry since 1978
- No form fill, nothing gated
What this calculator tells you
Add every air tool you run, set how often each one is actually in use, and get the CFM your system needs plus a recommended compressor horsepower class.
Your Air Tools
Results
Required compressor capacity at 100 PSI:
0 CFM
Recommended compressor class: 0 HP
At this size, compare fixed-speed vs variable-speed. If your demand swings, a VSD usually wins. See our VSD Savings Calculator.
How this is calculated
- Average demand per tool = tool CFM x quantity x duty cycle %.
- Required CFM = sum of all tool demands x (1 + safety margin %).
- Estimated HP = Required CFM / 4. Rule of thumb: an industrial rotary screw compressor delivers about 4 CFM per HP at 100 PSI.
- The HP estimate is rounded up to the nearest standard size: 5, 7.5, 10, 15, 20, 25, 30, 40, 50, 60, 75, 100, 125, 150, 200 HP.
Estimates only. Actual results depend on your equipment and operating conditions. Call 800.825.3222 for exact sizing.
Common questions
How many CFM do I need for my air compressor?
Add up the CFM rating of every air tool you run, multiplied by how many of each you have and the percentage of time each one actually runs (duty cycle). Then add a safety margin, typically 25 percent, for future growth and system losses. That total is the CFM your compressor needs to deliver at your required pressure.
How many CFM does an air compressor produce per horsepower?
A common rule of thumb for industrial rotary screw compressors is about 4 CFM per horsepower at 100 PSI. A 25 HP compressor delivers roughly 100 CFM. Actual output varies by manufacturer, model, and operating pressure, so confirm with the compressor data sheet before buying.
What is duty cycle and why does it matter for compressor sizing?
Duty cycle is the percentage of time a tool actually consumes air during a work period. A blow gun rated at 8 CFM used 30 percent of the time only averages 2.4 CFM of demand. Sizing on nameplate CFM alone oversizes the compressor and wastes energy. Sizing on realistic duty cycles matches the compressor to real demand.
Want a tech to verify these numbers at your facility?
Request received. If you need someone now, call 800.825.3222.
Please fill in all required fields (name, company, email, phone, preferred contact method, ZIP, and city), or call 800.825.3222.
These are estimates. An air audit gives you measurements.
A week of logged data on your actual system beats any rule of thumb. Our engineers run no-obligation compressed air audits across 14 Midwest locations.