Wrap & Paint Lab
Methodology
See how Wrap & Paint Lab separates geometry, allowance, coverage, labor, overhead, and uncertainty in its vehicle planning calculators.
Start with explicit inputs
Every calculation begins with values a user can see and edit. Product coverage, labor hours, transfer efficiency, prices, ratios, and package data are blank by default. The Use example control loads demonstration values only after the user asks for them.
Normalize first, round last
The browser normalizes lengths to millimetres, areas to square millimetres, liquids to millilitres, and currency to integer cents. Ratios and percentages remain finite decimal values. Raw calculations preserve precision; human-friendly rounding happens in the display layer.
Separate physical quantity from purchase quantity
The wrap tool distinguishes net geometric area, handling allowance, waste, packing loss, and rounded purchase units. The paint tool distinguishes sprayable quantity, ratio components, package quantity, and leftover. The panel cost tool distinguishes direct labor and materials from fees, overhead, contingency, and optional tax.
Keep uncertainty explainable
Wrap ranges change one named surface factor. Paint stages remain separate instead of blending unlike coverage assumptions. Panel-cost ranges require three explicit scenarios rather than a hidden percentage. Warnings identify factors that the model does not represent.
Version and review
Calculator outputs carry calculation version 1. Formula notes in this repository are the source for visible methodology summaries and automated numeric tests. A version changes when arithmetic meaning changes, not for copy or visual refinements. Demonstration assumptions remain launch-blocking until the owners listed in the editorial policy review them.
Last reviewed: by the Wrap & Paint Lab editorial team. Review the calculation methodology.