Horsepower And Torque Calculator

This calculator will help to calculate torque and Horsepower of an engine. Torque is all about the twisting force which makes an object rotate around its axis, like when you push a wrench to turn a bolt. Just like that, when an engine spinning, the torque tells you how powerful that rotation is. By simply entering the engine's horsepower and RPM, this calculator will help to find exactly how much torque is being produced or vice versa.

What is Torque?

Torque is the rotational equivalent of a linear force. It's the force that causes an object to rotate around an axis. Think of it this way: when you push a bolt, you're applying a linear force. But when you rotate it to tighten or loosen it, you're applying a rotational force. That's torque - the force applied to the wrench to make it turn. In both cases, there's a certain amount of force, but the direction of the force is different.

We measure torque in Newton-meters (N·m). Here's a simple way to visualize it: if you apply 1 newton of force on a 1-meter long arm at its end, you'll create 1 N·m of torque at the pivot point.

What is Horsepower?

Horsepower is a unit of measurement that tells you how much power is generated over time. The main difference between torque and horsepower is that torque is all about rotational force, while horsepower considers both force and time. More horsepower means an engine can do more work in less time. For example, a car with more horsepower can accelerate faster because it applies force more quickly, making the engine's RPM increase faster. In essence, horsepower is torque multiplied by RPM (HP = Torque × RPM).

What is RPM?

RPM stands for Revolutions Per Minute. It's a measure of how many times an object, like a car engine's crankshaft, rotates in one minute. Higher RPM means faster spinning.

Torque Equation

The equation for torque is:

τ = r × F × sin(θ)

Where:

• r is the lever arm (the distance between the pivot point and where the force is applied)
• F is the force acting on the object
• θ is the angle between the force vector and the lever arm (often 90° for maximum torque)
• τ is the torque itself, measured in newton-meters (N·m)

Let's look at an example:

Imagine you're tightening a bolt with a 1-foot wrench, applying 50 pounds of force at the end. The torque you generate is the product of the force and the wrench length (your lever arm).

Using the formula: Torque (lbf·ft) = Force (lbf) × Lever Arm (ft) In this case: Torque = 50 lbf × 1 ft = 50 lbf·ft

So, you're applying 50 pound-feet of torque to the bolt. Remember, a longer wrench or more force means more torque, making it easier to turn the bolt.

How Do I Calculate Torque from Horsepower?

To calculate torque from horsepower:

1. Measure the engine's horsepower (HP)
2. Record the engine's RPM
3. Use this formula: Torque (lb-ft) = (Horsepower (HP) × 5252) / RPM

This formula helps you figure out how much twisting force the engine produces at a given RPM. Read this article about the 5252 constant.

What is the SI unit of Torque?

The SI unit of torque is Newton-meter (N·m). In the imperial system, it's pound-force foot (lbf·ft).

How Do I Convert Torque from N·m to lbf·ft?

To convert torque from N·m to lbf·ft, divide by 1.355818 or multiply by 0.737562. For example, to convert 200 N·m:

200 × 0.737562 = 147.5124 lbf·ft

Remember, you can always use our torque calculator to make these conversions easier!