Convert Knot to Foot per Second (kn → ft/s)
The knot equals one nautical mile per hour and is the universal speed unit for ships and aircraft worldwide.
Knot to Foot per Second Conversion Table
10 common values| Knot | Foot per Second |
|---|---|
| 1 kn | 1.68781 ft/s |
| 5 kn | 8.439049 ft/s |
| 10 kn | 16.878098 ft/s |
| 25 kn | 42.195246 ft/s |
| 50 kn | 84.390492 ft/s |
| 100 kn | 168.78098 ft/s |
| 150 kn | 253.17148 ft/s |
| 200 kn | 337.56197 ft/s |
| 300 kn | 506.34295 ft/s |
| 500 kn | 843.90492 ft/s |
How to Convert Knot to Foot per Second Manually
Step by StepConverting knots to feet per second is straightforward: multiply by the conversion factor. Follow these three steps to do it by hand or in your head.
- 1Take your value in knotsStart with the number of knots (kn) you want to convert.
- 2Multiply by 1.68781The conversion factor from kn to ft/s is 1.68781. Multiply your value by this number.
- 3Read the result in feet per secondThe result is your value in feet per second (ft/s).
Formula
Multiply the value in knots by 1.68781. For the reverse direction, multiply by 0.592484.
ft/s = kn × 1.68781kn = ft/s × 0.592484Tips
Use these in everyday conversions- 1 knot = 1.852 km/h = 1.151 mph.
- Knots cannot be abbreviated "kt" in sailing — standard is "kn".
- A 40-knot wind is storm-force — 74 km/h.
Common Mistakes
Avoid these- Reading 40 knots as 40 km/h in weather — 74 km/h is much stronger.
- Using "knots per hour" — already a rate; it's just "knots".
- Treating knot as a distance unit — it's always a speed.
About Knot and Foot per Second
What is the Knot?
The knot equals exactly one nautical mile per hour (1.852 km/h or 0.5144 m/s) and is the universal speed unit for ships and aircraft worldwide. The name derives from the historical practice of measuring ship speed by counting knots tied at regular intervals along a 'log line' that was let out over the stern of a ship — the number of knots that passed in a given time gave the speed. International maritime regulations, aviation flight plans, and weather reports for sailors all use knots. A typical cruise ship sails at 18–22 knots, container ships at 18–25 knots, and commercial airliners at 470–500 knots cruise speed. The knot relates to km/h (1 knot ≈ 1.852 km/h), mph (1 knot ≈ 1.151 mph), m/s (1 knot ≈ 0.514 m/s), and the nautical mile (1 knot = 1 nmi/h). Wind speeds in aviation are also given in knots.
- Ship speeds and ocean currents
- Aircraft airspeed and ground speed
- Marine weather (wind reports in knots)
Airbus A380 cruise: ~490 knots. Cruise ship: 20 knots. Sailing yacht: 6 knots typical.
What is the Foot per Second?
Feet per second is the standard ballistics unit for projectile speeds, American sports analytics, and engineering. Bullet velocities are universally given in fps: a .22 LR bullet flies at about 1,200 fps, a 9 mm pistol round at 1,150 fps, and a high-velocity rifle round at 3,000 fps. American football and baseball analytics increasingly use fps for measuring throwing speed, ball exit velocity, and player movement. Engineering disciplines that retain US customary units (HVAC, civil engineering) often specify air or water flow speeds in fps. The unit relates to mph (1.467 fps = 1 mph), m/s (1 fps ≈ 0.305 m/s), and the knot (1 fps ≈ 0.592 kn). Outside ballistics and US sports, m/s and km/h dominate — but in their domains, fps remains entrenched in American technical practice.
- US ballistics and firearms
- US civil-engineering flow rates
- Older US physics and engineering texts
9mm bullet muzzle velocity: ~1150 ft/s. .308 rifle: ~2700 ft/s. Free fall terminal velocity: ~195 ft/s.