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Psi & Hose

CFM & Sizing

Air compressor CFM calculator

Tick the tools you own. We apply the published demand figures and our 25% margin, then show you which compressors in our roster clear the result - and the arithmetic behind it.

By Ryder M.Last updated Published
A calculator and notepad on a desk next to technical notes

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CFM calculator

Step 1 - tick the tools you own

Fastening
Automotive
Surface & finishing
Cutting & shaping
Air handling
Spraying & blasting

Step 2 - the number to shop above

6.25CFM @ 90 PSI

The arithmetic

Your thirstiest tool is the impact wrench, 1/2" at a published 5 CFM at 90 PSI. Times our 25% margin = 6.25 CFM. We do not add your other tools together, because you use one at a time.

Step 3 - compressors that clear it

  • Industrial Air ILA3606056 60-gallon11.5 CFM

Every demand figure comes from the same cited dataset as our air tool CFM chart. This is a single-operator home garage calculator - it does not sum simultaneous loads.

No black box

How this calculator works

Every figure it uses comes from the same dataset that drives our air tool CFM chart, and every one of those figures is cited to Ingersoll Rand, Engineering ToolBox, or the tool manufacturer. The calculator does three things: it finds the highest published demand among the tools you select, multiplies by 1.25, and then tells you which compressors clear that number.

It deliberately does not sum the demands of all your tools. In a home garage you use one air tool at a time. Summing them is how industrial sizing works, and applying industrial sizing to a one-person garage is precisely the overbuying this site exists to prevent. If you genuinely run two tools simultaneously, add the two highest figures yourself and size against that.

It also flags continuous-duty tools separately, because they change the nature of the answer rather than just the number. A continuous tool means the pump has to supply the whole demand on its own with no help from the tank, and duty cycle becomes a constraint alongside flow.

What it cannot do

It cannot account for your hose length, your fitting restrictions, the temperature of your garage, or the condition of your pump. That is what the 25% margin is for, and it is why the answer is a floor to shop above rather than an exact target.

From result to purchase

Compressors that clear the common answers

Four results cover most people who use this calculator. Under 3 CFM means nailing and inflation, and a standard pancake is the answer. Around 5 CFM means you have added a 1/2-inch impact, and either a high-pressure pancake or a 20-gallon unit works depending on whether you want flow or storage. Around 6 to 7 CFM means a ratchet or die grinder, and you need real pump output. Past 12 CFM means sanding or spraying, and you are shopping for a stationary machine.

Quick picks

#ProductBest forScorePrice
1
A red six-gallon pancake air compressor on a garage floor
Porter-Cable C20022.6 CFM @ 90 / 6 gal / 150 PSIThe default answer to 'cheapest useful compressor'. 6 gallons, 2.6 CFM, 150 PSI, and it has been the same machine for years.
A first compressor for nailing, inflation and burst automotive work3.6/10★★☆☆☆
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2
A high-capacity pancake air compressor with a roll cage
Metabo HPT EC914S (THE TANK)4 CFM @ 90 / 6 gal / 200 PSI4.0 CFM at 90 PSI and 200 PSI max - the only 6-gallon unit here that breaks the 2.6 CFM ceiling.
Getting real CFM without moving up to a 20-gallon footprint5.1/10★★★☆☆
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3
A ten-gallon vertical oil-free air compressor on wheels in a workshop
California Air Tools 10020C5.3 CFM @ 90 / 10 gal / 125 PSI / 70 dBA5.3 CFM at 70 dBA with a published 70/30 duty cycle. The first unit here that runs a continuous-duty tool.
Running a ratchet, die grinder or touch-up gun without waiting6.2/10★★★☆☆
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4
A twenty-gallon vertical air compressor standing against a garage wall
Husky C201H 20-gallon4 CFM @ 90 / 20 gal / 175 PSI / 83 dBA4.0 CFM with 20 gallons at 175 PSI. The cheapest way to buy STORAGE rather than flow.
Burst automotive work where tank volume, not CFM, is the limit6.3/10★★★☆☆
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Scores are computed from manufacturer-published specs by the rubric on our methodology page. Nothing here has been bench-tested, and we do not publish prices we cannot verify.

Pick 1 - Porter-Cable C2002

3.6/10★★☆☆☆

Porter-Cable C2002

Best for: A first compressor for nailing, inflation and burst automotive work

Verdict

The default answer to 'cheapest useful compressor'. 6 gallons, 2.6 CFM, 150 PSI, and it has been the same machine for years.

What it does well

  • 2.6 CFM at 90 PSI and 3.7 at 40 - the most common spec in the budget class for a reason
  • 6-gallon tank at 150 PSI stores enough air for real bursts of impact work
  • Two couplers, so two people or two tools without swapping

What it will not do

  • Porter-Cable does not publish a noise figure for it; the class sits in the high 70s to low 80s dBA
  • 2.6 CFM will not run a ratchet, die grinder or sander continuously
How this 3.6 was calculated
MetricScoreWeightBasis
Air flow3.640%2.6 CFM at 90 PSI, on a 0.7-6 CFM scale
Stored air2.325%6 gal x 150 PSI = 900, on a 125-3,500 scale
Noise5.015%Manufacturer publishes no dBA figure - scored a neutral 5, not a guess
Portability5.010%No weight published - scored a neutral 5
Spec transparency3.310%2 of 6 useful figures published (CFM at 90, CFM at 40, dBA, duty cycle, recovery, weight)
A red six-gallon pancake air compressor on a garage floor

Licensed stock photo - illustrative of the category, not a photo of this unit

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Published specs

Porter-Cable C2002 published specifications
CFM @ 90 PSI2.6
CFM @ 40 PSI3.7
Tank6 gal
Max pressure150 PSI
NoiseNot published
Duty cycleNot published
RecoveryNot published
PumpOil-free
Motor0.8
WeightNot published
Power120V

Source: Porter-Cable C2002 - product specifications

Pick 2 - Metabo HPT EC914S

5.1/10★★★☆☆

Metabo HPT EC914S (THE TANK)

Best for: Getting real CFM without moving up to a 20-gallon footprint

Verdict

4.0 CFM at 90 PSI and 200 PSI max - the only 6-gallon unit here that breaks the 2.6 CFM ceiling.

What it does well

  • 4.0 CFM at 90 PSI is 54% more air than the rest of the 6-gallon class
  • 200 PSI max means the same 6 gallons holds far more usable air
  • Clears the published average demand for a 1/2-inch impact and a 3/8-inch ratchet

What it will not do

  • 41 lb, the heaviest 6-gallon unit in the roster
  • Metabo HPT does not publish a noise figure, and high-pressure pumps are not quiet
How this 5.1 was calculated
MetricScoreWeightBasis
Air flow6.240%4 CFM at 90 PSI, on a 0.7-6 CFM scale
Stored air3.225%6 gal x 200 PSI = 1200, on a 125-3,500 scale
Noise5.015%Manufacturer publishes no dBA figure - scored a neutral 5, not a guess
Portability7.010%41 lb, on a 20-90 lb scale
Spec transparency3.310%2 of 6 useful figures published (CFM at 90, CFM at 40, dBA, duty cycle, recovery, weight)
A high-capacity pancake air compressor with a roll cage

Licensed stock photo - illustrative of the category, not a photo of this unit

Check price on Amazon

#ad Disclosure - we do not publish prices we cannot verify

Published specs

Metabo HPT EC914S (THE TANK) published specifications
CFM @ 90 PSI4
CFM @ 40 PSINot published
Tank6 gal
Max pressure200 PSI
NoiseNot published
Duty cycleNot published
RecoveryNot published
PumpOil-free
MotorNot published
Weight41 lb
Power120V

Source: Metabo HPT EC914S THE TANK - product specifications

Pick 3 - California Air Tools 10020C

6.2/10★★★☆☆

California Air Tools 10020C

Best for: Running a ratchet, die grinder or touch-up gun without waiting

Verdict

5.3 CFM at 70 dBA with a published 70/30 duty cycle. The first unit here that runs a continuous-duty tool.

What it does well

  • 5.3 CFM at 90 PSI clears every published figure for ratchets, die grinders and touch-up spraying
  • 70 dBA at that output is unusual - most 5+ CFM units are far louder
  • Publishes a real 70/30 duty cycle and a 25-second recovery from 95 to 125 PSI

What it will not do

  • 82.5 lb and 14 A - it needs its own circuit and it is not a carry-it-upstairs machine
  • 125 PSI max, so a bigger tank at higher pressure still stores more per fill
How this 6.2 was calculated
MetricScoreWeightBasis
Air flow8.740%5.3 CFM at 90 PSI, on a 0.7-6 CFM scale
Stored air3.325%10 gal x 125 PSI = 1250, on a 125-3,500 scale
Noise5.615%70 dBA, on a 58-85 dBA scale
Portability1.110%82.5 lb, on a 20-90 lb scale
Spec transparency10.010%6 of 6 useful figures published (CFM at 90, CFM at 40, dBA, duty cycle, recovery, weight)
A ten-gallon vertical oil-free air compressor on wheels in a workshop

Licensed stock photo - illustrative of the category, not a photo of this unit

Check price on Amazon

#ad Disclosure - we do not publish prices we cannot verify

Published specs

California Air Tools 10020C published specifications
CFM @ 90 PSI5.3
CFM @ 40 PSI6.4
Tank10 gal
Max pressure125 PSI
Noise70 dBA
Duty cycle70/30 (manufacturer-published)
Recovery120 s empty to full; 25 s recovery 95 to 125 PSI
PumpOil-free
Motor2.0
Weight82.5 lb
Power110V, 14 A

Source: California Air Tools 10020C - product specifications

Pick 4 - Husky C201H

6.3/10★★★☆☆

Husky C201H 20-gallon

Best for: Burst automotive work where tank volume, not CFM, is the limit

Verdict

4.0 CFM with 20 gallons at 175 PSI. The cheapest way to buy STORAGE rather than flow.

What it does well

  • 20 gallons at 175 PSI is roughly six times the stored air of a 6-gallon 150 PSI pancake
  • 4.0 CFM at 90 PSI and 5.2 at 40 - enough to recover between bursts instead of chasing you
  • Vertical footprint takes a corner instead of floor space

What it will not do

  • 83 dBA published and a 7-minute fill from empty - plan to switch it on before you start
  • Oil-free at 20 gallons means a shorter pump life than a cast-iron oil-lubricated unit
How this 6.3 was calculated
MetricScoreWeightBasis
Air flow6.240%4 CFM at 90 PSI, on a 0.7-6 CFM scale
Stored air10.025%20 gal x 175 PSI = 3500, on a 125-3,500 scale
Noise0.715%83 dBA, on a 58-85 dBA scale
Portability5.010%No weight published - scored a neutral 5
Spec transparency6.710%4 of 6 useful figures published (CFM at 90, CFM at 40, dBA, duty cycle, recovery, weight)
A twenty-gallon vertical air compressor standing against a garage wall

Licensed stock photo - illustrative of the category, not a photo of this unit

Check price on Amazon

#ad Disclosure - we do not publish prices we cannot verify

Published specs

Husky C201H 20-gallon published specifications
CFM @ 90 PSI4
CFM @ 40 PSI5.2
Tank20 gal
Max pressure175 PSI
Noise83 dBA
Duty cycleNot published
Recoveryabout 7 minutes to fill from empty
PumpOil-free
Motor1.3 running
WeightNot published
Power120V

Source: Husky C201H 20-gallon compressor - retailer specification listing

Check our arithmetic

Worked example, by hand

Say you select a framing nailer, tire inflation and a 1/2-inch impact wrench. The published demands are 2.5 CFM, 2 CFM and 4 to 5 CFM. The highest is 5. Multiply by 1.25 and you get 6.25 CFM.

Nothing in the 6-gallon pancake class clears 6.25 CFM. The Metabo HPT EC914S at 4.0 CFM gets closest and, because an impact wrench is burst duty, its 6 gallons at 200 PSI cover the gap in practice. The California Air Tools 10020C at 5.3 CFM is closer on flow but stores less. The honest answer is that either works for occasional wheel work and neither is comfortable for a full brake job.

That ambiguity is the real output of a sizing exercise, and it is why a calculator that spits out a single number without showing its working is doing you a disservice. The number tells you where the edge is. Whether you want to live at the edge is your call.

FAQ

Questions people actually ask

Should I add up the CFM of all my air tools?

Not for a one-person home garage, where you use one tool at a time - size against the highest single demand plus a margin. Add them only if you genuinely run two tools simultaneously, or if someone else is working off the same compressor.

Why does the calculator apply a 25% margin?

To cover pressure drop through hose and fittings, a pump delivering less than rated once it is hot, and the tool you will buy next year. We use 25% rather than the 50% to 100% some industrial guides recommend, because those margins assume continuous shift work rather than weekend bursts.

Can I use this to size a shop compressor?

No. It is built for a single-operator home garage and deliberately does not sum simultaneous loads. For a multi-bay shop you need proper system sizing with diversity factors, and the CAGI handbook is the right starting point.

What if my tool is not in the list?

Read the CFM at 90 PSI off your tool's own spec sheet and size against that figure times 1.25. The manufacturer's number for your specific tool always beats a class average, including ours - Ingersoll Rand says the same thing on its own chart.

Sources

Where these numbers come from

Accessed September 2026. If a figure on this page does not match the manufacturer's current sheet, tell us at contact@psiandhose.com and we will correct and date the change - see our editorial policy.

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