For general cleanup in a 2-car garage with mixed debris, a wheeled 8–14 gallon vac in the 5–6 peak HP range, delivering 75–150 CFM with about 65 inches of water lift, covers almost everything. That's the general-purpose class, and it's the sweet spot for most homeowners. Step up to 12–14 gallons if you're also handling wood chips or larger volumes of debris.

No. Tank size only determines how often you stop to empty it — it has no effect on suction. A 16-gallon vac and a 6-gallon vac with identical motors pick up identically; the big one just holds more. Oversized units are heavier, harder to store, and awkward for detail work. Size the tank to your debris volume, and size the motor to your airflow and water-lift needs.

Not in any useful way. Peak HP is a brief laboratory figure recorded under conditions the motor never sustains in normal use, and it can't be compared reliably across brands. Treat it as a rough class indicator only. Airflow in CFM tells you how well the vac moves dust and debris, and water lift in inches tells you how well it pulls liquids and handles restricted hoses or clogged filters.

CFM measures the volume of air the vac moves per minute — that's what carries sawdust, drywall dust and loose debris up the hose. Water lift measures raw pulling strength in inches, which matters when the airflow is restricted: wet pickup, heavy or dense material, long hose runs, and filters that are loading up. Dust collection is an airflow job; flood cleanup is a water-lift job. Most tasks need a sensible balance of both.

Detailing is the one job where smaller genuinely wins. A compact 2–6 gallon unit in the 1–4.5 HP range, around 60–75 CFM, is enough for interiors. Reach, hose flexibility and crevice access matter far more than raw power, and a large vac is simply unwieldy around seats and footwells. The calculator won't recommend a heavy-duty unit for detailing even if you select a large garage — the task drives the result, not the room.

Prioritize airflow, not gallons. In a 2-car workshop, look for 8–14 gallons with 125–150 CFM; for a large shop running a stationary setup, 16+ gallons with 175+ CFM is appropriate. Note that a shop vac is a high-suction, low-volume tool — it excels at sanders, track saws and cleanup, but it isn't a substitute for a dedicated dust collector on large machines like a planer or jointer. Fine dust also demands a proper fine-dust filter or bag.

Usually yes, and space size matters less than you'd expect. Even in a small room, wet cleanup calls for at least 8–14 gallons with 65+ inches of water lift, because water is heavy and small tanks fill fast. For serious flood work in a large area, you're into 16+ gallons with 175+ CFM and 75+ inches of water lift. Always confirm the model is rated wet/dry and remove the dry filter before picking up liquids.

Jobsite work sits in the medium-to-heavy range. For a medium site with mixed debris, 8–14 gallons at 125–150 CFM works well. Large sites with chips, offcuts and heavy construction debris justify 16+ gallons, 6+ HP and 175+ CFM. Durability and mobility matter as much as specs here — big wheels, a protected motor housing and a tough hose determine whether the vac survives the year.

It weighs all four inputs but ranks them: primary task first, then debris type, then space size, then portability. That ordering prevents common sizing mistakes — a large garage won't push you to a 16+ gallon unit if you only detail cars, and a small room won't leave you undersized for flood cleanup. Portability nudges the result but never overrides a genuine performance requirement, so choosing "handheld" for wet cleanup still returns a realistic recommendation.

No. VacMatch returns spec ranges only — no products, brands or prices. The bands come from published general sizing guidance: light-duty 2–6 gallons, general-purpose 8–14 gallons, heavy-duty 16+ gallons, with matching HP, CFM and water-lift targets. Use the output as a shopping filter: any vac meeting those numbers should handle your work. Treat it as practical guidance rather than a laboratory measurement.