Foot-Pounds per Second to Watts Converter

Convert power between foot-pounds per second (ft⋅lb/s) and watts (W) instantly, with precise factors, formulas, and worked examples.

ft⋅lb/s ⇄ W Power Converter

ft⋅lb/s

Power in imperial units.

W

Power in SI units.

Precision:

Quick ft⋅lb/s to W reference

ft⋅lb/s Watts (W)

How to convert foot-pounds per second to watts

Foot-pounds per second (ft⋅lb/s) and watts (W) are both units of power – the rate at which work is done or energy is transferred.

Conversion factor

\(1\ \text{ft⋅lb/s} = 1.3558179483\ \text{W}\)

\(1\ \text{W} = 0.7375621493\ \text{ft⋅lb/s}\)

Formula: ft⋅lb/s → W

\(P_{\text{W}} = P_{\text{ft⋅lb/s}} \times 1.3558179483\)

Example: Convert 10 ft⋅lb/s to watts.

  1. Write the formula: \(P_{\text{W}} = P_{\text{ft⋅lb/s}} \times 1.3558179483\)
  2. Substitute: \(P_{\text{W}} = 10 \times 1.3558179483\)
  3. Compute: \(P_{\text{W}} ≈ 13.558\ \text{W}\)

Formula: W → ft⋅lb/s

\(P_{\text{ft⋅lb/s}} = \dfrac{P_{\text{W}}}{1.3558179483}\)

Example: Convert 100 W to ft⋅lb/s.

  1. Write the formula: \(P_{\text{ft⋅lb/s}} = P_{\text{W}} / 1.3558179483\)
  2. Substitute: \(P_{\text{ft⋅lb/s}} = 100 / 1.3558179483\)
  3. Compute: \(P_{\text{ft⋅lb/s}} ≈ 73.756\ \text{ft⋅lb/s}\)

Where does the conversion factor come from?

The watt is defined in SI units as:

  • 1 W = 1 joule per second (1 J/s)
  • 1 joule = 1 newton·meter (1 N⋅m)

The foot-pound (ft⋅lb) is an imperial unit of work or energy:

  • 1 ft⋅lb = 1 pound-force × 1 foot
  • 1 lbf = 4.4482216153 N
  • 1 ft = 0.3048 m

So:

\(1\ \text{ft⋅lb} = 4.4482216153\ \text{N} \times 0.3048\ \text{m} ≈ 1.3558179483\ \text{J}\)

Therefore, \(1\ \text{ft⋅lb/s} = 1.3558179483\ \text{J/s} = 1.3558179483\ \text{W}\).

Relation to horsepower

Horsepower is another common unit of power in mechanical and automotive contexts. The mechanical horsepower is defined as:

\(1\ \text{hp} = 550\ \text{ft⋅lb/s} ≈ 745.7\ \text{W}\)

Using this, you can quickly estimate:

  • 1 ft⋅lb/s ≈ 0.001818 hp
  • 1 W ≈ 0.001341 hp

Common values

  • 1 ft⋅lb/s ≈ 1.356 W
  • 5 ft⋅lb/s ≈ 6.779 W
  • 50 ft⋅lb/s ≈ 67.79 W
  • 100 ft⋅lb/s ≈ 135.58 W
  • 500 ft⋅lb/s ≈ 677.91 W

FAQ

Is foot-pounds per second a unit of power or energy?

Foot-pounds (ft⋅lb) alone measure energy or work. When divided by time (per second), ft⋅lb/s becomes a unit of power, just like watts.

How precise is this converter?

Internally, the calculator uses the full double-precision factor 1.3558179483. You can choose how many decimal places to display (2–6) using the precision selector.

When should I use ft⋅lb/s vs watts?

Use ft⋅lb/s in traditional mechanical or imperial engineering contexts (e.g., older machinery specs). Use watts in scientific, electrical, and most modern engineering applications. This converter lets you move seamlessly between the two.