We show the source, the math, and what is still missing.

HitchMargin is an independent towing-planning utility for conventional bumper-pull trailers. It helps people compare ratings and weights they have verified themselves. It does not certify a combination, replace a manufacturer instruction, or turn an incomplete vehicle identity into a capacity claim.

How the calculator is reviewed

The calculation engine is kept separate from the interface and covered by deterministic tests. Payload, trailer rating, receiver, GCWR, tongue, and rear-axle checks remain separate so a favorable result in one comparison cannot hide a missing or exceeded limit elsewhere. Every calculation change requires a regression test before release.

How guides are researched

Guides favor primary sources: vehicle and equipment manufacturers, NHTSA, regulations, and scale-operator instructions. Each guide names its references and review date. Search snippets, dealer claims, forum posts, and model-line maximums are not treated as exact-vehicle ratings.

Why some answers stay incomplete

A VIN decoder can identify useful vehicle facts without resolving every axle ratio, package, label value, installed component, or manufacturer rating row. When a controlling fact is unresolved, HitchMargin keeps the missing check visible. A future vehicle record may be published only with a precise source location, configuration key, review state, reviewer, and explicit human publication action.

Corrections and independence

The calculator result is sponsor-neutral. Advertising, affiliates, and paid data cannot change a rating, warning, formula, or missing-check state. To report a source change or calculation concern, email support@hitchmargin.com without including a VIN or other sensitive information.

Scope

HitchMargin Editorial is not presented as a licensed engineer, vehicle manufacturer, installer, or legal authority. The exact vehicle, trailer, hitch, tire, and equipment labels and instructions, actual scale weights, operating conditions, and applicable law remain controlling.