Convert Gallons per Day per Square Foot to mm/h
1 US gallon per day per square foot (gpd/ft²) = 1.697743056 millimetres per hour (mm/h). 1 mm/h = 0.5890172819 gpd/ft². Example: 15 gpd/ft² = 15 × 1.697743056 = 25.46614583 mm/h.
Also searched as US gallons per day per square foot to mm/h, US gallons per day per square foot in mm/h, US gallons per day per square foot into millimetres per hour, gpd/ft2 to mm/h, gpd/ft2 in millimetres per hour, gpd/ft2 into millimetre per hour, US gallon per day per square foot to millimetre per hour, gpd/ft2 to millimetres per hour converter, US gallons per day per square foot to millimeters per hour and how many millimetres per hour in a US gallon per day per square foot.
1 gpd/ft² = 1.697743056 mm/h
Type in either box. Scientific notation works: 1.5e-3.
Converting a list? Use the bulk gpd/ft² to millimetre per hour converter to paste a column from Excel.
How to Convert Gallon per Day per Square Foot to Millimetre per Hour
- 1 gpd/ft² = 1.697743056 mm/h
- 1 mm/h = 0.5890172819 gpd/ft²
- Example: convert 15 gpd/ft² to mm/h: 15 gpd/ft² = 15 × 1.697743056 mm/h = 25.46614583 mm/h
Formula
mm/h = gpd/ft² × 1.697743055556
Derivation from SI units:
- 1 gpd/ft² = 0.003785411784 m³ ÷ 86,400 s ÷ 0.09290304 m².
- 1 mm/h = 0.001/3600 m/s.
- 1 gpd/ft² = 4.715952932099 × 10⁻⁷ m/s ÷ 2.777777777778 × 10⁻⁷ m/s per mm/h = 1.697743055556 mm/h
Both units are defined exactly, so the factor is exact. Gallon per Day per Square Foot definition: US gallon per day per square foot; Millimetre per Hour definition: millimetre per hour.
Worked examples
- A reading of 100 gpd/ft² converts to 169.7743056 mm/h.
100 gpd/ft² × 1.697743056 = 169.7743056 mm/h - A value of 1000 gpd/ft² is 1697.743056 mm/h.
1000 gpd/ft² × 1.697743056 = 1697.743056 mm/h
Gallon per Day per Square Foot to Millimetre per Hour conversion table
| Gallons per Day per Square Foot (gpd/ft²) | Millimetres per Hour (mm/h) |
|---|---|
| 1 gpd/ft² | 1.697743056 mm/h |
| 10 gpd/ft² | 16.97743056 mm/h |
| 50 gpd/ft² | 84.88715278 mm/h |
| 100 gpd/ft² | 169.7743056 mm/h |
| 200 gpd/ft² | 339.5486111 mm/h |
| 500 gpd/ft² | 848.8715278 mm/h |
| 1000 gpd/ft² | 1697.743056 mm/h |
| 2000 gpd/ft² | 3395.486111 mm/h |
| 5000 gpd/ft² | 8488.715278 mm/h |
| 10000 gpd/ft² | 16977.43056 mm/h |
Where it's used
Gallons per Day per Square Foot are used for older USGS and well-driller 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.
Gallon per Day per Square Foot to other hydraulic conductivity units
| Conversion | 1 gpd/ft² equals |
|---|---|
| gpd/ft² to millimetre per hour | 1.697743056 mm/h |
| gpd/ft² to metre per second | 4.715952932 × 10⁻⁷ m/s |
| gpd/ft² to centimetre per second | 0.00004715952932 cm/s |
| gpd/ft² to metre per day | 0.04074583333 m/day |
| gpd/ft² to centimetre per hour | 0.1697743056 cm/h |
| gpd/ft² to foot per day | 0.1336805556 ft/day |
| gpd/ft² to inch per hour | 0.06684027778 in/h |
Frequently asked questions
How many millimetres per hour are in 1 US gallon per day per square foot?
1 gpd/ft² = 1.697743056 mm/h.
How do I convert US gallons per day per square foot to millimetres per hour?
Multiply the value in gpd/ft² by 1.697743056. For example, 15 gpd/ft² × 1.697743056 = 25.46614583 mm/h.
Is the gpd/ft² to mm/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
- 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, "gallon (U.S.)".
- 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). Convert Gallons per Day per Square Foot to mm/h. Retrieved October 29, 2026, from https://scientificconverters.com/hydraulic-conductivity/gallons-per-day-per-square-foot-to-millimeters-per-hour/
IEEE
Scientific Converters, "Convert Gallons per Day per Square Foot to mm/h," scientificconverters.com. Accessed: Oct. 29, 2026. [Online]. Available: https://scientificconverters.com/hydraulic-conductivity/gallons-per-day-per-square-foot-to-millimeters-per-hour/