Centimetres per Hour to Inches per Hour (cm/h to in/h)

Formula

in/h = cm/h × 0.3937007874016

or in/h = cm/h ÷ 2.54

Derivation from SI units:

• 1 cm/h = 0.01/3600 m/s.
• 1 in/h = 0.0254/3600 m/s.
• 1 cm/h = 0.000002777777777778 m/s ÷ 0.000007055555555556 m/s per in/h = 0.3937007874016 in/h

Both units are defined exactly, so the factor is exact. Centimetre per Hour definition: centimetre per hour; Inch per Hour definition: inch per hour.

Worked examples

1. A reading of 2 cm/h converts to 0.7874015748 in/h.
   2 cm/h × 0.3937007874 = 0.7874015748 in/h
2. A value of 6.25 cm/h is 2.460629921 in/h.
   6.25 cm/h × 0.3937007874 = 2.460629921 in/h

Where it's used

Centimetres per Hour are used for infiltration capacity and Horton’s equation, while inches per hour appear in USDA soil survey permeability classes. Both measure hydraulic conductivity (coefficient of permeability k), so the conversion is a fixed factor.

Centimetre per Hour to other hydraulic conductivity units

Frequently asked questions

Sources

• The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures , Table 4 (derived units) and Table 8 (non-SI units accepted for use with the SI).
• Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "inch".

Last reviewed: 2026-10-15. Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.