Window calculators & converters

Free, no-signup tools for US builders and architects working with European windows - unit conversions and cost estimates I reach for on real projects.

U-Factor to R-Value Converter

Convert a window U-factor to its R-value and back, with typical single, double, and triple-glazed values.

Open tool →

U-Value to U-Factor Converter

Convert European metric U-value (W/m2K) to US imperial U-factor - the spec check every import project needs.

Open tool →

European Window Cost Estimator

Enter your areas and get a live landed-cost range across three tiers, duties and freight included.

Open tool →