What this tool answers
You need a first-pass parallel-clamp size before buying. Enter needed jaw opening in inches. The calculator names the smallest class on this site’s ladder — 24, 30, or 36 in — or returns NO_MATCH. It is not an F-clamp selector (see other portfolio tools) and not a pipe-clamp calculator.
Opening vs throat depth
Jaw opening is the maximum span between jaws. Throat depth is how far the bar reaches from the edge. A large opening with a shallow throat still fails deep-in-panel clamp lines — always confirm both on the listing.
Class ladder on this site
Classes use published VEVOR US parallel clamp jaw openings checked 2026-09-10: 24 in, 30 in, and 36 in 2-pack parallel F-clamp sets (~1500 lb load claim on these SKUs). Matching rule: smallest class where published jaw opening ≥ needed inches.
When the answer is NO_MATCH
If needed opening exceeds 36 in, this site returns NO_MATCH. Typical next steps: a longer parallel clamp, pipe clamps, or a different workholding plan. Do not force a 36 in clamp past this screen.
Sources
VEVOR US parallel bar-clamp product pages for jaw opening claims (checked 2026-09-10). OSHA hand-tool and eye-protection practice for pinch and slip hazards. Distinct from F-clamp opening charts elsewhere in the portfolio.