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Feet & Inches to MM Converter

Convert feet and inches to millimeters (mm) instantly with worked calculation steps.

How to use it

  • Enter feet and inches to calculate millimeters.

Examples

5 ft 6 in1676.4 mm

This converts feet and inches into total inches (feet × 12 + inches), then multiplies by the exact factor 25.4 mm per inch to get millimeters — the precision engineering drawings and manufacturing specs typically need.

5 ft 6 in = 66 inches. 66 × 25.4 = 1676.4 mm.

Where this comes up

  • Converting an imperial measurement (feet and inches) into mm for a CAD drawing, CNC job or manufacturing spec
  • Comparing a US doorway, clearance or furniture dimension against a European mm-based product
  • Woodworking and metalworking plans that mix imperial reading with metric tooling
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Last updated 18 August 2026