Measurement Methodology

The rules behind our diagrams, tables, calculators and model-specific data.

How BathSpecs turns technical dimensions into practical fit checks.

Use finished surfaces

We identify the actual wall, floor, deck, curb or opening from which a purchasing measurement should be taken. Rough framing is labeled separately.

A product category name or nominal size is not treated as a substitute for the manufacturer dimension drawing.

Core dimensions are presented in U.S. customary units and metric equivalents where practical, with the original source unit retained.

Model-specific entries retain the manufacturer, model number, source URL and review date so changes can be detected.

Local code, accessibility requirements, substrate, structural support and professional installation are called out when they can change the decision.