Start from the tool, not the tank
Pneumatic tools need both pressure and airflow. Most shop tools list SCFM (or CFM) near 90 PSI. That delivery number is what this site screens. Tank gallons store air between motor cycles; a larger tank can feel smoother on intermittent tools, but it does not raise the compressor’s sustained CFM @ 90 PSI.
Duty factors used here
Duty 1 (intermittent) multiplies tool SCFM by 1.0 — appropriate for short bursts such as brad nailers and many lug-nut impact jobs. Duty 2 (frequent) uses 1.25 when the tool fires often with little recovery. Duty 3 (continuous) uses 1.5 for tools that stay on, such as dual-action sanders and many spray guns. These factors follow common shop-sizing practice that compares delivered CFM with a margin for continuous draw; they are not a laboratory test of your specific hose and fittings.
Portable class ladder on this site
ShopCFM maps required delivery to three verified VEVOR US portable classes: 2.2 CFM @ 90 PSI (example 4.6 gal), 3.35 CFM @ 90 PSI (example 6.3 gal), and 5.3 CFM @ 90 PSI (example 10 gal). The smallest class that meets or exceeds the required figure is shown. Requirements above 5.3 CFM return NO_MATCH instead of recommending an undersized portable unit.
Typical tool SCFM reference points
Published consumer charts often place brad nailers near 0.5–1 SCFM, framing nailers near 2–2.5 SCFM, 1/2 in impact wrenches near 4–5 SCFM intermittent, and continuous sanders or HVLP guns well above 6–10 SCFM. Always prefer your tool’s nameplate over a chart average. Sources reviewed for this methodology include Air Compressor Zone tool CFM charts and manufacturer compressor buying guidance that emphasize CFM @ working pressure.
Limits and honesty rules
This screen does not account for long hose pressure drop, altitude, simultaneous tools, 100% duty commercial production, or stationary two-stage shop compressors beyond the portable ladder. Affiliate tracking is pending. Product links are ordinary VEVOR merchant URLs checked on 2026-09-10; availability can change. Pair this compressor check with a hose-capacity check when the run is long — that is a different problem than CFM delivery.