Required CFM
4 CFM
PSI
90
Tank
6 gal
HP
1.0
Impact Wrench (1/2")
5 CFM @ 90 PSI
Impact Wrench (3/4")
7 CFM @ 90 PSI
Die Grinder
5 CFM @ 90 PSI
Air Ratchet
3.5 CFM @ 90 PSI
Blow Gun
2.5 CFM @ 90 PSI
Brad / Finish Nailer
2.2 CFM @ 90 PSI
Framing Nailer
2.5 CFM @ 120 PSI
HVLP Spray Gun
12 CFM @ 30 PSI
DA Sander
8 CFM @ 90 PSI
Air Drill
4 CFM @ 90 PSI
Cutoff Tool
6 CFM @ 90 PSI
Tire Inflator
1.5 CFM @ 120 PSI
Sandblaster
14 CFM @ 90 PSI
Plasma Cutter
6 CFM @ 90 PSI
50% for home shop, 75%+ for production
Recommended Compressor
4 CFM
@ 90 PSI
Tank
6 gal
Motor
1.0 HP
Inputs
Result
Raw CFM: 5.0 + 2.5 = 7.5. At 50% simultaneous use: 7.5 × 0.50 = 3.75. With 1.5x safety: 3.75 × 1.5 = 5.63 → 6 CFM. Tank = 6 × 1.5 = 9 gallons.
Inputs
Result
Raw CFM: 5 + 8 + 5 = 18. At 50%: 18 × 0.50 = 9.0. With 1.5x: 9.0 × 1.5 = 13.5 → 14 CFM. Tank = 14 × 1.5 = 21 gallons.
List all air tools you'll use, note their CFM requirements, estimate what percentage will run simultaneously, and multiply by 1.5x safety factor. A home garage with an impact wrench (5 CFM) and blow gun (2.5 CFM) at 50% simultaneous use needs: 7.5 × 0.50 × 1.5 = 5.6 CFM compressor.
| Tool | CFM Required | PSI | Usage Pattern |
|---|---|---|---|
| Impact Wrench 1/2" | 5.0 | 90 | Intermittent |
| DA Sander | 8.0 | 90 | Continuous |
| HVLP Spray Gun | 12.0 | 30 | Continuous |
| Framing Nailer | 2.5 | 120 | Intermittent |
| Sandblaster | 14.0 | 90 | Continuous |
Tank size determines how long you can work before the compressor cycles on. Rule of thumb: 1 gallon per CFM for intermittent use (nailers), 1.5–2 gallons per CFM for continuous tools (sanders, spray guns). A 20 CFM setup needs a 30–40 gallon tank for continuous use.
Single-stage compressors pump air to final pressure in one stroke, maxing out around 150 PSI. Two-stage compressors use two cylinders: the first compresses to ~90 PSI, the second boosts to 175+ PSI. Two-stage units run cooler, last longer, and are more efficient for continuous-use tools.
A rough rule is 4 CFM per HP for single-stage and 5 CFM per HP for two-stage. So a 10 CFM requirement needs about 2.5 HP single-stage or 2 HP two-stage. Beware of inflated HP ratings on cheap compressors — look at actual CFM delivery at 90 PSI instead.
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Last Updated: Mar 19, 2026
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