🎓 Engineering • Mechanical Engineering
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Torque & Rotational Horsepower Calculator
Converts between rotational force moment (N·m / ft·lb) and mechanical shaft power (kW / HP).
Torque, Lever Arm & Rotational Horsepower
Computes moment of force ($\tau = F \cdot r \sin\theta$) and converts shaft rotational speed to Kilowatts and Horsepower
Mechanical Force & Engine Presets
Torque Lever Arm & Tangential Vector Decomposition
Torque τ = F · r · sin(θ) = 150 N × 0.4 m × sin(90°) = 60 N·m (44.25 ft·lb)
Power P = (2π · N · τ) / 60 = (2π × 3000 × 60) / 60 = 18.85 kW (25.28 HP)
Torque (SI)
60 N·m
531 in·lbTorque (Imperial)
44.25 ft·lb
Foot-poundsMechanical Power
25.28 HP
25.63 PS metricPower in Kilowatts
18.85 kW
18849.6 WattsWhat is Torque?
Torque is the rotational equivalent of linear force, measuring the tendency of a force to cause an object to rotate about an axis.
Formula & Step-by-Step Calculation
τ = F · r · sin(θ), Power P = (2π · N · τ) / 60, HP = P_watts / 745.7
Torque moment and shaft rotational power equation.
Worked Step-by-Step Examples
Example 1
Calculate torque of 150 N applied perpendicularly at 0.4 m radius at 3,000 RPM
Solution: Torque: 60.00 N·m (44.25 ft·lb), Power: 18.85 kW (25.28 HP)
• τ = 150 × 0.4 = 60 N·m; P = (2π × 3000 × 60) / 60 = 18,849.5 W = 18.85 kW = 25.28 HP
Common Real-World & Academic Use Cases
- ✓ Automotive engine dyno horsepower verification
- ✓ Electric vehicle traction motor sizing
- ✓ Bolted flange torque wrench tightening specifications
How to Use the Torque & Rotational Horsepower Calculator
1
Input Force & Radius
Specify applied force (N) and lever arm (m).
2
Input Shaft RPM
Enter rotation speed.
3
Read Torque & Horsepower
Review output torque and horsepower ratings.
Frequently Asked Questions
Q: What is the relationship between torque and horsepower at 5,252 RPM?
In imperial units (HP = Torque × RPM / 5252), horsepower and torque (in ft·lb) are always exactly equal at 5,252 RPM.