Air Compressor CFM & Tank Sizing Tool
Tick off the air tools, CNC machines and looms you run at the same time to see how much air you need, what size compressor to buy and how big a tank to fit.
Air compressor CFM & tank
Size a compressor for the air tools you actually run.
Tools running at the same time
Typical air use at about 90 PSI (6 bar) is shown under each tool.
- Paint spray gun10 CFM each0
- Air riveter4 CFM each0
- Impact wrench (1/2")5 CFM each0
- Impact wrench (1")10 CFM each0
- Air drill4 CFM each0
- Die / angle grinder6 CFM each0
- Air hammer / chisel4 CFM each0
- Blow gun3 CFM each0
- Orbital sander8 CFM each0
- Small sandblaster15 CFM each0
- CNC tool changer / clamps3 CFM each0
- Plasma cutter (40A)6 CFM each0
- Pneumatic cylinder / press2 CFM each0
- Air-jet loom25 CFM each0
- Tyre inflator2 CFM each0
From a machine's manual, e.g. a laser's assist air.
Add the air tools you run at the same time.
How this is calculated
- 1
Add up the air demand
Each tool's typical free-air use at about 90 PSI (6 bar), times how many run together, plus any machine you enter by hand.
- 2
Add a 25% margin
Every air system leaks, tools wear and draw more air, and workshops grow. The total is increased by 25%.
- 3
Compressor size
Piston compressors give about 3.5 CFM per HP, screw compressors about 4.2. Above roughly 35 CFM a screw compressor is recommended for continuous duty.
- 4
Tank size
About 10 litres of receiver per CFM, rounded up to a standard tank. A bigger tank smooths demand peaks and lets the compressor rest between cycles.
Frequently asked questions
How many CFM does a paint spray gun need?
Most spray guns need 8 to 12 CFM, and HVLP guns can need more. Check the gun's rating and size for the highest one you use.
Piston or screw compressor?
A piston compressor suits intermittent work up to about 30 to 35 CFM. For continuous use, CNC machines, textile looms or anything above that, a screw compressor lasts longer and costs less to run per CFM.
What size air tank do I need?
As a rule of thumb, about 10 litres per CFM of demand. A 40 CFM system pairs well with a 500 litre receiver. More storage helps if demand comes in bursts.
What pressure should my compressor deliver?
Most tools run at 6 to 7 bar (90 to 100 PSI). Choose a compressor rated about 1 bar above your highest tool pressure to cover pipe and filter losses.