Millimetre per Hour (mm/h)
Millimetres per hour measure infiltration and sprinkler application rates; a sprinkler must apply water slower than the soil’s basic infiltration rate, often 5–25 mm/h.
Symbol: mm/h
Quantity: hydraulic conductivity (coefficient of permeability k)
SI relation: 1 mm/h = 2.777777777778 × 10⁻⁷ m/s (exact)
Derivation: 1 mm/h = 0.001/3600 m/s.
Exact: yes, by definition
Typical uses
- Sprinkler application rate versus infiltration
- Rainfall intensity in the rational method
- Drip and sprinkler design
Convert millimetres per hour to other units
| Conversion | 1 mm/h equals | Reverse |
|---|---|---|
| millimetre per hour to metre per second | 2.777777778 × 10⁻⁷ m/s | metre per second to millimetre per hour |
| millimetre per hour to centimetre per second | 0.00002777777778 cm/s | centimetre per second to millimetre per hour |
| millimetre per hour to metre per day | 0.024 m/day | metre per day to millimetre per hour |
| millimetre per hour to centimetre per hour | 0.1 cm/h | centimetre per hour to millimetre per hour |
| millimetre per hour to foot per day | 0.07874015748 ft/day | foot per day to millimetre per hour |
| millimetre per hour to inch per hour | 0.03937007874 in/h | inch per hour to millimetre per hour |
| millimetre per hour to gpd/ft² | 0.5890172819 gpd/ft² | gpd/ft² to millimetre per hour |
Open the Hydraulic Conductivity Converter (cm/s, m/day) to convert any value between all units.
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).
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
Cite this page
APA
Scientific Converters. (2026, October 15). Millimetre per Hour (mm/h). Retrieved October 29, 2026, from https://scientificconverters.com/units/millimeter-per-hour/
IEEE
Scientific Converters, "Millimetre per Hour (mm/h)," scientificconverters.com. Accessed: Oct. 29, 2026. [Online]. Available: https://scientificconverters.com/units/millimeter-per-hour/