What size compressor do you need for sandblasting?

Only for very small nozzles (3–4 mm) and short bursts — not continuous work. A 50 L tank with a 300 L/min pump empties in under a minute on a #5 nozzle. You need both adequate L/min AND enough tank to smooth pressure dips, or a screw compressor for serious blasting.

1 CFM ≈ 28.3 L/min. A 550 L/min nozzle need is ~19.5 CFM at the tool; with 30% margin the compressor should deliver ~25 CFM sustained. US datasheets use CFM; European labels use L/min — convert before comparing.

Stay at 4 mm or smaller at 7 bar (~400 L/min demand). A 5 mm needs 550 L/min — you will wait for the tank to refill constantly. Either upsize the compressor or downsize the nozzle and accept slower production.

Nameplate L/min is often measured at empty tank and ideal conditions. Hoses, filters, moisture separators and heat build-up reduce real delivery. Running at 100% duty cycles kills home compressors — 70–80% load extends motor life.