What this tool answers
You need a first-pass bench-vise size before buying. Enter the maximum jaw opening you need in inches. The calculator names the smallest class on this site’s ladder — 4 in, 6 in, or 8 in jaw — that clears the published max opening, or returns NO_MATCH. It is not a structural engineering check, mounting plan, or substitute for manufacturer instructions.
Why max opening matters
Retail vise listings often lead with jaw width, but the clampable span is the max jaw opening. Matching your required opening to published maxOpen avoids undersizing against a thick workpiece or oversizing without a transparent class ladder.
Class ladder on this site
Classes use published VEVOR US bench-vise ratings checked 2026-09-10: (1) 4 in jaw with 4.7 in max open, (2) 6 in jaw with 6 in max open, (3) 8 in jaw with 8 in max open (forward). Matching rule: smallest class where class.maxOpen ≥ opening_in.
When the answer is NO_MATCH
If required opening exceeds 8 in, this site returns NO_MATCH for its published ladder. Typical next steps: confirm units (inches vs mm), check for a larger industrial vise outside this screen, or follow shop equipment guidance. Do not force an undersized vise.
Mounting, rating, and pinch points
Bolt the vise to a sturdy bench before use. Never use it as a press or anvil substitute beyond the rated capacity. Wear eye protection. Keep hands clear of pinch points when closing jaws. Pipe jaws have their own diameter limits — flat-jaw opening does not replace those ratings.
Sources
VEVOR US bench-vise product pages for jaw width and max opening claims dated in products.json (checked 2026-09-10). Consumer sizing practice pairing required opening with published maxOpen. Safety framing follows common manufacturer warnings: secure mounting, rated capacity, eye protection, pinch points, and separate pipe-jaw limits.