Guide

How wet/dry shop vac size calculators work

Plain-language guide to sizing a portable wet/dry shop vacuum from cleanup area and debris type, with 4–11 gal classes and NO_MATCH.

What this tool answers

You need a first-pass portable wet/dry vac tank class for a US garage, shop bay, or car detail job. The calculator scales cleanup area by debris type, then names the smallest class on this ladder (4, 8, or 11 gal) — or returns NO_MATCH.

Why debris type matters

Wet and flood jobs fill tanks faster and need wet filters. Fine dry dust needs good filtration more than raw gallons. Factors 1.0 / 1.5 / 2.2 are transparent screens — not a full airflow model.

Safety limits

Never vacuum gasoline, solvents, or other flammable vapors with a consumer wet/dry vac. Empty liquids promptly; keep filters matched to wet vs dry mode.

When the answer is NO_MATCH

If tank demand exceeds 11 gal-eq on this ladder, the site returns NO_MATCH. Split zones or use a larger commercial extractor — do not force an 11 gal consumer class.

Sources

VEVOR US wet/dry vac pages for 4 / 8 / 11 gal tanks (HTTP 200, 2026-09-10). Complementary to DustCFM (tool dust collection), not a duplicate intent.

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