Authoritative definitions of the International System of Units and SI prefixes.
Dedicated unit pair
Knots to Feet per second
Convert kn to ft/s instantly, then review the formula, assumptions, and rounding guidance.
Speed & accelerationInstant result
Decimals
Formula result = input × 0.5144444444 ÷ 0.3048. 1 kn = 1.6878 ft/s
Common examples
One value, several units
Metres per second0.5144 m/s
Kilometres per hour1.852 km/h
Miles per hour1.1508 mph
Feet per second1.6878 ft/s
Mach (standard atmosphere)0.0015 Ma
Conversion table
| kn | ft/s |
|---|---|
| 1 kn | 1.6878 ft/s |
| 2 kn | 3.3756 ft/s |
| 5 kn | 8.439 ft/s |
| 10 kn | 16.8781 ft/s |
| 25 kn | 42.1952 ft/s |
| 50 kn | 84.3905 ft/s |
| 100 kn | 168.781 ft/s |
Conversion chart
1 kn1.6878 ft/s
5 kn8.439 ft/s
10 kn16.8781 ft/s
25 kn42.1952 ft/s
50 kn84.3905 ft/s
Worked example
100 km/h is approximately 62.137 mph.
Unit definition
Knots (kn) One knots equals 0.5144444444 metre per second.
Unit history
Knots is represented here using its modern SI definition or an internationally accepted relationship to an SI base unit.
Step by step
1. Parse the value, including fractions.
2. Convert kn to metre per second.
3. Convert the base value to ft/s and apply your display precision.
Important
Mach uses 343 m/s, a representative dry-air value near 20 °C.
Understand the result before using it
Knots to Feet per second converts a value measured in Knots (kn) into the equivalent value in Feet per second (ft/s). The numerical value changes because the size and definition of the selected unit changes; the underlying quantity does not.
Calculated result
The conversion follows the displayed unit relationship. Display rounding can hide additional digits, and measured inputs cannot become more accurate merely by changing units.
Formula, assumptions, and example
Formula
result = input × 0.5144444444 ÷ 0.3048
Assumptions
- Knots and Feet per second represent the same speed quantity.
- The input is expressed in kn; the output is expressed in ft/s.
- Mach uses 343 m/s, a representative dry-air value near 20 °C.
Worked example
1 kn = 1.68780985696 ft/s. For another value, apply the same relationship and round only to the precision your source measurement supports.
When to use it
Good uses
- Read a kn measurement in a document that expects ft/s.
- Compare a knots value with a value reported in feet per second.
- Check the kn-to-ft/s arithmetic before copying the result into another calculation.
Limitations
Common mistakes to avoid
- Mach varies with the local speed of sound; this tool uses the representative condition stated beside the converter.
- Round the output to a precision justified by the original measurement.
- Verify safety-critical, regulated, laboratory, and contractual conversions against the controlling standard.
Sources and further reading
These references explain the underlying standards or provide authoritative context. Your own contract, institution, clinician, product documentation, local code, or governing standard may be the controlling source.
Guidance on unit names, symbols, conversions, and numerical presentation.
Questions about this calculation
How do I convert Knots to Feet per second?
result = input × 0.5144444444 ÷ 0.3048 Using the displayed relationship, 1 kn equals 1.68780985696 ft/s.
How many Feet per second are in one Knots?
One Knots is 1.68780985696 Feet per second. The displayed digits may be rounded.
Can I reverse the kn to ft/s conversion?
Yes. Swap the source and target units in the converter. The reverse relationship converts ft/s back to kn.
Is the Knots to Feet per second result exact?
The conversion follows the displayed unit relationship. Display rounding can hide additional digits, and measured inputs cannot become more accurate merely by changing units.