Torque Calculator: Your Instant Solution for Finding Torque from Power and RPM

Use our free torque calculator. Enter input values to calculate torque.

Pro Tip: Use a screen capture tool to clip the graph for your application. We also have other torque articles in our article repository.

Why a Torque Calculator Is a Game-Changer

In industrial settings, quick and accurate torque calculations are vital—whether you’re sizing gearboxes, selecting motors, or diagnosing underperformance. But without a reliable calculator, these tasks can be slow and error‑prone.

Our torque calculator gives you instant torque values in both lb‑ft and Newton‑meters (Nm). Plus, it visually plots how torque changes with speed in a torque‑speed curve. It’s intuitive, powerful, and tailored for engineers and maintenance professionals.

Want to explore the deeper relationship between torque and speed? Check out Torque vs. Speed: The Fundamental Trade‑off in Power Transmission for the full breakdown.

What Is Torque and Why It Matters

Torque = rotational force—the measure of how much twisting power a motor or gearbox can deliver. A higher torque means better ability to move heavy machinery; lower torque generally permits higher speeds.

In power systems, torque determines whether your equipment can start under load, accelerate, or lift. It’s essential in gearbox and motor design.

Standard Torque Formulas

Depending on your unit system:

• Imperial (HP & RPM):
  Torque (lb‑ft) = (Horsepower × 5252) ÷ RPM
• Metric (kW & RPM):
  Torque (Nm) = (Kilowatts × 9550) ÷ RPM

These formulas show the balance between torque, speed, and power. As RPM increases, torque decreases—an essential mechanical trade‑off.

How to Use the Calculator

1. Choose units: Imperial (HP, lb‑ft) or Metric (kW, Nm)
2. Input values: horsepower (or kW) and RPM
3. Click “Calculate”
4. Instant result: torque displayed in both lb‑ft and Nm
5. Interactive Curve: optional torque‑speed chart visualizes performance across RPM range

Why This Calculator Outshines Generic Tools

Basic calculators just output one number. Ours offers:

• Fully functional unit toggle (Imperial ↔ Metric)
• Three calculation modes: torque from HP/RPM, RPM from HP/torque, power from torque/RPM
• A dynamic torque-speed graph with adjustable RPM slider
• Responsive, accessible design, perfect for desktop and mobile use

Real-World Use Cases

• Gearbox Selection: Ensure you choose a model that can handle required torque.
• Motor Comparison: Balance horsepower and RPM to match your system.
• Troubleshooting: Check if under‑torque is causing equipment stalls or slow starts.
• Operational Design: Plan for proper torque in robotics, mixers, conveyors, and more.

Example Calculations

These are quick with the calculator—no guesswork or manual math required.

FAQ – Frequently Asked Questions

How accurate is the calculator?

Highly accurate, using standard engineering formulas for torque, power, and speed.

Can I calculate torque without knowing RPM?

No. You need at least two variables (HP and RPM or kW and RPM) to compute torque.

What’s the difference between lb-ft and Nm?

They’re both torque units. 1 lb-ft ≈ 1.3558 Nm; the calculator shows both outputs automatically.

Why does torque decrease as RPM increases?

That’s due to the inverse relationship between torque and speed at constant power—covered more deeply in our Torque vs. Speed piece.

Related Articles

Bearings for Gearbox: What to Know, Where to Buy

DC Motor: Ultimate Guide to Types, Uses, and Where to Buy

Single-Phase vs Three-Phase Electric Motors: A Comprehensive Guide

Torque vs. Speed: The Fundamental Trade-off in Power Transmission

Understanding Gear Ratios: How Speed Reducers Work

Conclusion

When you need torque numbers—fast and precise—a specialized torque calculator is indispensable. It saves time, improves accuracy, and enhances your content’s SEO value.

For deeper insights, don’t miss our article on the nuances of torque and speed dynamics: Torque vs. Speed: The Fundamental Trade-off in Power Transmission.