Feet per Day to Millimetres per Hour (ft/day to mm/h)
1 foot per day (ft/day) = 12.7 millimetres per hour (mm/h). 1 mm/h = 0.07874015748 ft/day. Example: 15 ft/day = 15 × 12.7 = 190.5 mm/h.
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1 ft/day = 12.7 mm/h
Type in either box. Scientific notation works: 1.5e-3.
Converting a list? Use the bulk foot per day to millimetre per hour converter to paste a column from Excel.
How to Convert Foot per Day to Millimetre per Hour
- 1 ft/day = 12.7 mm/h
- 1 mm/h = 0.07874015748 ft/day
- Example: convert 15 ft/day to mm/h: 15 ft/day = 15 × 12.7 mm/h = 190.5 mm/h
Formula
mm/h = ft/day × 12.7
Derivation from SI units:
- 1 ft/day = 0.3048/86,400 m/s.
- 1 mm/h = 0.001/3600 m/s.
- 1 ft/day = 0.000003527777777778 m/s ÷ 2.777777777778 × 10⁻⁷ m/s per mm/h = 12.7 mm/h
Both units are defined exactly, so the factor is exact. Foot per Day definition: foot per day; Millimetre per Hour definition: millimetre per hour.
Worked examples
- A reading of 3 ft/day converts to 38.1 mm/h.
3 ft/day × 12.7 = 38.1 mm/h - A value of 50 ft/day is 635 mm/h.
50 ft/day × 12.7 = 635 mm/h
Foot per Day to Millimetre per Hour conversion table
| Feet per Day (ft/day) | Millimetres per Hour (mm/h) |
|---|---|
| 0.01 ft/day | 0.127 mm/h |
| 0.1 ft/day | 1.27 mm/h |
| 1 ft/day | 12.7 mm/h |
| 3 ft/day | 38.1 mm/h |
| 10 ft/day | 127 mm/h |
| 30 ft/day | 381 mm/h |
| 50 ft/day | 635 mm/h |
| 100 ft/day | 1270 mm/h |
| 300 ft/day | 3810 mm/h |
| 1000 ft/day | 12700 mm/h |
Where it's used
Feet per Day are used for USGS aquifer reports, while millimetres per hour appear in sprinkler application rate versus infiltration. Both measure hydraulic conductivity (coefficient of permeability k), so the conversion is a fixed factor.
Foot per Day to other hydraulic conductivity units
| Conversion | 1 ft/day equals |
|---|---|
| foot per day to millimetre per hour | 12.7 mm/h |
| foot per day to metre per second | 0.000003527777778 m/s |
| foot per day to centimetre per second | 0.0003527777778 cm/s |
| foot per day to metre per day | 0.3048 m/day |
| foot per day to centimetre per hour | 1.27 cm/h |
| foot per day to inch per hour | 0.5 in/h |
| foot per day to gpd/ft² | 7.480519481 gpd/ft² |
Frequently asked questions
How many millimetres per hour are in 1 foot per day?
1 ft/day = 12.7 mm/h.
How do I convert feet per day to millimetres per hour?
Multiply the value in ft/day by 12.7. For example, 15 ft/day × 12.7 = 190.5 mm/h.
Is the ft/day to mm/h conversion exact?
Yes. Both units are defined exactly, and 1 ft/day is exactly 12.7 mm/h.
Sources
- 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, "foot".
- 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). Feet per Day to Millimetres per Hour (ft/day to mm/h). Retrieved October 29, 2026, from https://scientificconverters.com/hydraulic-conductivity/feet-per-day-to-millimeters-per-hour/
IEEE
Scientific Converters, "Feet per Day to Millimetres per Hour (ft/day to mm/h)," scientificconverters.com. Accessed: Oct. 29, 2026. [Online]. Available: https://scientificconverters.com/hydraulic-conductivity/feet-per-day-to-millimeters-per-hour/