Distance divided by time.
Foot per Days to mph Converter — ft/d to mph
Convert Foot per Days (ft/d) to mph (mph) using the exact conversion factor (1 foot per days = 0.0000078914 mph). See the formula, worked examples, conversion table, history, and common uses.
Foot per Days to mph converter
Converter
Speed Converter
Convert road, aviation, marine, lab, and scientific speed units.
Context values
Some unit families need one extra value for a physically accurate result.
Miles per hour.
Result = input x 3.52777778e-6 / 0.44704.
Speed uses meters per second as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Foot per Days to mph
Foot per Days and mph both describe speed, and the conversion matters whenever a maritime or aviation speed (knots) needs to be compared against a road speed (mph). Specifically: Distance divided by time, and miles per hour.
Formula
mph = foot per days × 0.00000789141414141
This factor comes from each unit's defined relationship to the category's base unit: 1 foot per days equals 0.00000352777777778 base units, and 1 mph equals 0.44704 base units, so dividing one by the other gives the direct foot per days-to-mph factor of 0.00000789141414141.
Simple example
1 ft/d × 0.000007891414141 = 0.0000078914 mph
1 foot per days = 0.0000078914 mph.
Real-world example
10 ft/d × 0.000007891414141 = 0.0000789141 mph
10 foot per days = 0.0000789141 mph.
Conversion table
| Foot per Days (ft/d) | mph (mph) |
|---|---|
| 1 ft/d | 0.0000078914 mph |
| 5 ft/d | 0.0000394571 mph |
| 10 ft/d | 0.0000789141 mph |
| 25 ft/d | 0.0001972854 mph |
| 50 ft/d | 0.0003945707 mph |
| 100 ft/d | 0.0007891414 mph |
Reverse conversion: mph to Foot per Days
0.0000078914 mph × 126720 = 0.999998208 ft/d
0.0000078914 mph = 0.999998208 foot per days.
foot per days = mph × 126720
For a page dedicated to this direction, see mph to Foot per Days.
Understanding the Foot per Days (ft/d)
Distance divided by time.
Understanding the mph
mph (mph) measures speed. Miles per hour follows directly from the international statute mile (1,609.344 m) divided by one hour. It is classified as a US/imperial customary unit.
Where it's used: United States (road speed limits and vehicle speedometers) United Kingdom (road speed limits)
Uses of the mph today
- Road speed limits and vehicle speedometers in the US and UK
- Weather reporting (wind speed) in the US
- Sports statistics (e.g. pitch speed, wind gusts) in US media
History of the mph
Miles per hour is a compound unit with no separate origin story of its own — it follows automatically once the statute mile was fixed at 5,280 feet in 1593 and later refined to exactly 1,609.344 meters by the 1959 international agreement that also standardized the pound.
Historical origin. mph was not the invention of a single named person; it developed through the process described above.
mph — sources
- NIST — International yard and pound (1959) — Basis for the modern mile used in mph.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many mph are in 1 foot per days?
1 foot per days equals 0.0000078914 mph, using the exact defined conversion factor rather than an estimate.
How do I convert foot per days to mph?
Multiply the foot per days value by 0.000007891414141. The converter above does this instantly to whatever precision you set.
How do I convert mph back to foot per days?
Use the reverse factor: 1 mph equals 126,720 foot per days. You can also use the swap control in the converter above to flip the direction instantly.
What is a foot per days?
Foot per Days (ft/d) is a unit of speed.
What is a mph?
mph (mph) measures speed. Miles per hour follows directly from the international statute mile (1,609.344 m) divided by one hour. It is classified as a US/imperial customary unit.
Is the foot per days to mph conversion exact?
Yes. Both foot per days and mph are defined by fixed standards rather than physical artifacts, so the factor of 0.000007891414141 used above is exact to as many digits as you choose to display.