Convert speed units — km/h, mph, m/s, knots, mach and more.
| Unit | Name | Value |
|---|---|---|
| 0.001 kn | 0.00168781 ft/s | |
| 0.01 kn | 0.0168781 ft/s | |
| 0.1 kn | 0.168781 ft/s | |
| 1 kn | 1.68781 ft/s | |
| 5 kn | 8.43904 ft/s | |
| 10 kn | 16.8781 ft/s | |
| 50 kn | 84.3904 ft/s | |
| 100 kn | 168.781 ft/s | |
| 1000 kn | 1687.81 ft/s |
Common knot values converted to foot per second — factor: 1 kn = 1.688 ft/s
| Knot (kn) | Foot per Second (ft/s) | Context |
|---|---|---|
| 1 kn | 1.688 ft/s | Light air |
| 5 kn | 8.439 ft/s | Light breeze |
| 10 kn | 16.88 ft/s | Fresh breeze |
| 15 kn | 25.32 ft/s | Strong wind |
| 20 kn | 33.76 ft/s | Strong wind |
| 30 kn | 50.63 ft/s | Gale |
| 50 kn | 84.39 ft/s | Storm |
| 80 kn | 135 ft/s | Violent storm |
| 100 kn | 168.8 ft/s | Strong gale |
| 137 kn | 231.2 ft/s | Cat 5 hurricane |
| 200 kn | 337.6 ft/s | Fast patrol boat |
| 300 kn | 506.3 ft/s | Hydrofoil |
| 400 kn | 675.1 ft/s | Jet airliner |
| 490 kn | 827 ft/s | Jet airliner |
| 600 kn | 1,013 ft/s | Fast jet |
Converting knot to foot per second is essential for drivers, pilots, engineers, and scientists working across different measurement systems. Road speed limits, aviation airspeed, nautical navigation, and physics calculations each use different speed units, making quick and accurate conversion a practical everyday skill.
Key reference points: 5 kn = 8.439 ft/s and 10 kn = 16.88 ft/s. At higher speeds, 100 kn = 168.8 ft/s. For reverse conversion, multiply ft/s values by 0.5925 to get back to kn.
All conversions use the internationally recognized factor of exactly 1 kn = 1.688 ft/s. Calculations are performed in IEEE 754 double-precision floating point, giving accuracy to at least 8 significant figures — more than sufficient for any practical application.
Formula: Foot per Second = Knot × 1.6878084
Multiply any knot value by 1.6878084 to get foot per second. One knot equals 1.6878084 ft/s.
Reverse: Knot = Foot per Second × 0.59248431
1 kn = 1.6878084 ft/s. Memorize this for instant mental estimates.
Use 1.6878 as a quick mental multiplier.
To verify: multiply your result by 0.59248431 to recover the original kn value.
Monitors vessel speed, current, and wind speed in knots for navigation.
Reads airspeed indicators in knots and files flight plans in knots.
Issues speed instructions to aircraft in knots.
Issues gale and storm warnings with wind speeds in knots.
Optimizes sail trim and routing for maximum boat speed in knots.
Reports submerged and surface speeds in knots for tactical planning.
The knot is a unit of speed equal to one nautical mile per hour, approximately 1.852 km/h or 0.514 m/s. Its name comes from the historical practice of measuring ship speed by counting knots on a rope thrown overboard.
Knots are the international standard for maritime and aviation speed. All commercial aircraft, warships, and weather forecasts use knots. Air traffic control worldwide communicates in knots and feet.
Interesting fact: The cruising speed of a Boeing 747 is about 490 knots (907 km/h). Ocean currents are typically 0.5-1 knot, while Category 5 hurricanes sustain winds above 137 knots.
Feet per second is an Imperial unit of speed equal to exactly 0.3048 m/s. It was in common use in Britain and America from the 17th century, particularly in ballistics and military applications.
ft/s remains the standard in US ballistics: bullet velocities, muzzle speeds, and arrow velocities are universally quoted in feet per second. It also appears in HVAC airflow measurements and some engineering contexts.
Interesting fact: A typical rifle bullet travels at 900-1,200 ft/s (270-370 m/s). The speed of sound at sea level is approximately 1,125 ft/s.