What this tool answers
You need a first-pass handheld induction heater class for rusty US shop fasteners. The calculator scales diameter by rust severity, then names the smallest class on this ladder (1,100, 1,500, or 1,800 W) — or returns NO_MATCH.
Why rust severity matters
Seized joints need more energy and longer heat. Factors 1.0 / 1.25 / 1.55 are transparent screens — not a full thermal model of every alloy.
Coil fit and safety
Published consumer kits often cite ~5–40 mm heating range. The coil must fit; keep fuel and plastics clear; respect max continuous run times on the nameplate.
When the answer is NO_MATCH
If watt demand exceeds 1,800 W-eq on this ladder, the site returns NO_MATCH. Use a higher-duty system or mechanical extraction — do not force an 1,800 W consumer class.
Sources
VEVOR US induction bolt-heater pages for 1,100 / 1,500 / 1,800 W (HTTP 200, 2026-09-10). Complementary to torch/heat-gun shopping, not a duplicate garage-heater intent.