CBS technical guide · Compressor sizing

Air compressor sizes: what tank and HP do I need?

Short answer: the tank (liters/gallons) is your air buffer — autonomy and stable pressure — while the motor HP determines the airflow (CFM) the unit can sustain. Light intermittent tools run on 25–50 liters (7–13 gal); a clinic or small shop works well with 50–100 liters (13–26 gal); a shop that paints or sands daily needs 235–300 liters (62–80 gal) and 3–5 HP; and for continuous demand or multiple drop points, step up to 500–1,000 liters or a rotary screw compressor. The golden rule: size by your tools’ CFM, not just by tank liters.

Tank = air buffer
HP = sustained CFM
Size by CFM +25–50%
Continuous duty → screw

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How many liters (gallons) does my compressor need?

The tank doesn’t produce air: it stores it. A bigger tank gives more autonomy between motor starts, steadier pressure and more rest for the motor. Here is the reference by size, with the CBS unit for each range:

Tank	Typical use	CBS reference unit
4–25 L (1–7 gal)	Airbrushing, inflation, hobby work	Oil-free 0.65 HP / 4 L portable — 62 dB(A)
50 L (13 gal)	Dental office, light intermittent tools	Oil-free 2 HP / 13 gal vertical — 3.53 CFM, 69 dB(A)
100–140 L (26–37 gal)	Clinics, labs, light shop work	Oil-free 3.5 HP / 26 gal
150–235 L (40–62 gal)	Mid-size shop, painting by sessions	Air•co 2 HP / 150 L · 3 HP / 235 L
300 L (80 gal)	Body shop, tire shop, metalwork	CBS XV 5 HP / 80 gal — 22.38 CFM, 175 psi
500 L (132 gal)	Heavy duty with several drop points	CBS XV 5 HP / 500 L (up to 15 HP)
1,000 L (264 gal)	Plant or air network with high demand	CBS XV / Air•co duplex, 20–30 HP

All CBS tanks from 150 liters up comply with Mexico’s NOM-020-STPS pressure-vessel standard.

And how much HP? Horsepower rules the airflow

Motor HP determines how many CFM the compressor can deliver continuously — and that is the number that must exceed your tools’ consumption. With factory specs from CBS units:

Motor	Airflow (CBS units)	Enough for
1–2 HP	3.5–9 CFM	Nailers, inflation, airbrushing, one touch-up gun
3 HP	13 CFM	HVLP gun, small shop running one tool at a time
5 HP	22.38 CFM	Full shop: painting cars, DA sander, impact wrench
7.5–15 HP	30–60 CFM	Industrial cycle duty, several simultaneous tools
10 HP screw	30.02 CFM continuous	Continuous production, no rest cycles — see the Air•co 10 HP
20+ HP screw	80+ CFM	Plant with an air network — see the screw series

The sizing rule: add up the CFM of the tools you’ll run at the same time, multiply by 1.25–1.5, and pick a motor that delivers it. Then choose the tank for your usage pattern: intermittent = moderate tank; sustained = big tank or rotary screw. You can convert between CFM, L/min and HP with our unit converter.

Big tank with a small motor, or big motor with a small tank?

If your use comes in bursts (impact wrench, nailer): a generous tank with a moderate motor works — the buffer absorbs the peaks and the motor recovers between uses. That’s the case for the 5 HP with a 500 L tank: maximum autonomy on the same pump head.

If your use is sustained (painting, sanding, a production line): no tank makes up for an undersized motor — it drains and pressure drops mid-task. Here motor CFM rules, and if demand runs for hours, a rotary screw delivers continuous flow with no rest cycles.

The most-searched sizes, solved with CBS units

13 gallon · oil-freeOil-Free 2 HP / 50 L (13 gal)3.53 CFM (110 L/min) · 116 psi
Vertical · 69 dB(A) · oil-free airView product

26 gallon · oil-freeOil-Free 3.5 HP / 100 L (26 gal)8.47 CFM (240 L/min) · 116 psi
Horizontal · 72 dB(A) · oil-free airView product

The workhorse 5 HPCBS XV Piston 5 HP / 80 gal22.38 CFM (633 L/min) · 175 psi
Cast-iron pump head · NOM-020 tankView product

10 HP rotary screwAir•co 10 HP Rotary Screw30.02 CFM @ 145 psi · continuous
Direct drive · acoustic cabinetView product

Listed airflows are factory specs for each model. Torn between two sizes? Contact us and we’ll size it with your actual tools — free of charge.

Frequently asked questions

What do a compressor’s liters (or gallons) mean?

It’s the storage tank’s capacity, not how much air the unit produces. Two 26-gallon compressors can deliver very different airflows: the motor and pump head produce the air (CFM); the tank only stores it.

Is a 100-liter (26 gal) compressor enough for painting?

It depends on the motor, not the liters. An HVLP gun consumes 9–15 CFM, and 100-liter units usually carry 2–3.5 HP motors that sustain less than that. For painting by sessions, start at 150–235 liters with 2–3 HP; for full cars, 5 HP with an 80-gallon tank. Details in our painting compressor guide.

Which matters more: tank size or HP?

Cover the airflow first: the motor must deliver more CFM than your simultaneous tools consume, with a 25–50% margin. Once airflow is covered, more liters add autonomy and stability. A huge tank with a short motor just takes longer to drain — it doesn’t fix the deficit.

When should I choose oil-free vs lubricated?

Oil-free when the process can’t tolerate lubricant traces: dental offices, clinics, labs — and they run quieter. Lubricated (with proper air treatment) for rough shop and industrial duty: more airflow and service life under intensive use. On their upkeep, see the oil guide.

Prefer us to size it for you? We are CBS Compresores: compressed air solutions since 1971, with spare parts, service and free technical advice across Mexico. Call our national line 800 611 1249 or contact us.