Millimetres per Hour to Inches per Hour (mm/h to in/h)
1 millimetre per hour (mm/h) = 0.03937007874 inches per hour (in/h). 1 in/h = 25.4 mm/h. Example: 15 mm/h = 15 × 0.03937007874 = 0.5905511811 in/h.
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1 mm/h = 0.03937007874 in/h
Type in either box. Scientific notation works: 1.5e-3.
Converting a list? Use the bulk millimetre per hour to inch per hour converter to paste a column from Excel.
How to Convert Millimetre per Hour to Inch per Hour
- 1 mm/h = 0.03937007874 in/h
- 1 in/h = 25.4 mm/h
- Example: convert 15 mm/h to in/h: 15 mm/h = 15 × 0.03937007874 in/h = 0.5905511811 in/h
Formula
in/h = mm/h × 0.03937007874016
or in/h = mm/h ÷ 25.4
Derivation from SI units:
- 1 mm/h = 0.001/3600 m/s.
- 1 in/h = 0.0254/3600 m/s.
- 1 mm/h = 2.777777777778 × 10⁻⁷ m/s ÷ 0.000007055555555556 m/s per in/h = 0.03937007874016 in/h
Both units are defined exactly, so the factor is exact. Millimetre per Hour definition: millimetre per hour; Inch per Hour definition: inch per hour.
Worked examples
- A reading of 10 mm/h converts to 0.3937007874 in/h.
10 mm/h × 0.03937007874 = 0.3937007874 in/h - A value of 50 mm/h is 1.968503937 in/h.
50 mm/h × 0.03937007874 = 1.968503937 in/h
Millimetre per Hour to Inch per Hour conversion table
| Millimetres per Hour (mm/h) | Inches per Hour (in/h) |
|---|---|
| 1 mm/h | 0.03937007874 in/h |
| 2 mm/h | 0.07874015748 in/h |
| 5 mm/h | 0.1968503937 in/h |
| 10 mm/h | 0.3937007874 in/h |
| 15 mm/h | 0.5905511811 in/h |
| 25 mm/h | 0.9842519685 in/h |
| 50 mm/h | 1.968503937 in/h |
| 75 mm/h | 2.952755906 in/h |
| 100 mm/h | 3.937007874 in/h |
| 150 mm/h | 5.905511811 in/h |
Where it's used
Millimetres per Hour are used for sprinkler application rate versus infiltration, 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.
Millimetre per Hour to other hydraulic conductivity units
| Conversion | 1 mm/h equals |
|---|---|
| millimetre per hour to inch per hour | 0.03937007874 in/h |
| millimetre per hour to metre per second | 2.777777778 × 10⁻⁷ m/s |
| millimetre per hour to centimetre per second | 0.00002777777778 cm/s |
| millimetre per hour to metre per day | 0.024 m/day |
| millimetre per hour to centimetre per hour | 0.1 cm/h |
| millimetre per hour to foot per day | 0.07874015748 ft/day |
| millimetre per hour to gpd/ft² | 0.5890172819 gpd/ft² |
Frequently asked questions
How many inches per hour are in 1 millimetre per hour?
1 mm/h = 0.03937007874 in/h.
How do I convert millimetres per hour to inches per hour?
Multiply the value in mm/h by 0.03937007874, or divide it by 25.4. For example, 15 mm/h × 0.03937007874 = 0.5905511811 in/h.
Is the mm/h to in/h conversion exact?
Yes. Both units are defined exactly, so the ratio is exact; its decimal form does not terminate and is shown here to 10 significant figures (more with the precision selector).
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: . 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). Millimetres per Hour to Inches per Hour (mm/h to in/h). Retrieved October 29, 2026, from https://scientificconverters.com/hydraulic-conductivity/millimeters-per-hour-to-inches-per-hour/
IEEE
Scientific Converters, "Millimetres per Hour to Inches per Hour (mm/h to in/h)," scientificconverters.com. Accessed: Oct. 29, 2026. [Online]. Available: https://scientificconverters.com/hydraulic-conductivity/millimeters-per-hour-to-inches-per-hour/