Window calculators & converters
Free, no-signup tools for US and Canadian builders and architects working with European windows - unit conversions and cost estimates I reach for on real projects. A window's R-value is 1 divided by its U-factor, and a European U-value in W/(m2.K) becomes a US U-factor when you multiply it by 0.17611. The converters below do both, with charts and worked examples.
U-Value / U-Factor to R-Value Calculator & Converter
R-value = 1 / U-factor, both directions. Calculate a window's R-value from its U-value or U-factor, or go from R-value to U-value - metric W/m2K accepted - with a window R-value chart and worked examples.
Open tool →Metric U-Value to Imperial U-Factor
U-factor = metric U-value x 0.17611 (and back with x 5.678). Converts both ways: a European or Canadian U-value in W/m2K to the US U-factor, and back - the spec check every import project needs - with a U-value chart for windows.
Open tool →European Window Cost Estimator
Upload a PDF, Excel or CSV schedule or type your areas and get a budget range across four tiers with destination-specific import and freight assumptions. Canadian GST and buyer clearance are separate; hub freight is provisional. uPVC, aluminum, and aluminum-clad wood as a wider budget range; final wood quotes come from drawings.
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