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Trade unit converter

Convert length, area, volume, pressure, power, flow, temperature and more, plus fractional inches to millimetres.

Updated: Oct 2026.

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Convert units

Fractional inches to millimetres

Notes

  • 1 inch is exactly 25.4 mm and 1 foot is exactly 0.3048 m.
  • Canadian (Imperial) and US gallons differ: 4.54609 L and about 3.785412 L.
  • Pressure in inches of water and inches of mercury uses NIST's conventional values.
  • Results are rounded to six decimal places.

Sources

  1. NIST Special Publication 811, Appendix B.8 — Factors for units listed alphabetically (opens in a new tab)

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