Horsepower Calculator

How to Use This Horsepower Calculator

Power ratings hide behind a wall of unit names—watts, mechanical HP, metric PS, BTU/h on HVAC plates. I reach for this when a spec sheet lists kilowatts but the motor plate I am holding says horsepower, or when I need to sanity-check work done from force and distance numbers in a lab setup.

Definition calculator

• Enter Force. Input the applied force and choose newtons, kilonewtons, pound-force, or kilogram-force.
• Enter Distance. Type how far the force moves the load—meters, kilometers, miles, or yards.
• Enter Time. Record how long the move took in seconds, minutes, hours, or days.
• Press Calculate. Results show power in watts plus a table of equivalent horsepower and related units.

Unit converter

• Enter Amount. Type the known power value.
• Select Convert From and Convert To. Choose watt, kilowatt, mechanical/metric/electrical/boiler horsepower, or BTU/h.
• Press Calculate. The converted value appears in the selected output unit.

For vehicle power from quarter-mile track data, use the Engine Horsepower Calculator, which applies drag-strip ET and trap-speed formulas instead of raw force-distance work.

Horsepower Formulas and Practical Applications

Power is work per unit time—how fast you move a load, not just whether you can move it. James Watt defined mechanical horsepower so steam-engine buyers could compare machines to draft horses: 550 pound-feet of work per second.

Power = (Force × Distance) ÷ Time

The definition calculator converts your inputs to SI units (newtons, meters, seconds), computes watts, then divides by each power unit's watt equivalent. Example: 10 newtons moving a load 3 meters in 2 seconds yields 15 watts—far below one horsepower, which equals 745.7 watts mechanical.

Historical anchor

Lifting 550 pounds one foot in one second is exactly one mechanical horsepower. That concrete image beats memorizing conversion factors when you are explaining motor sizing to someone on a job site.

Standard Units and Conversion Tables

Horsepower is not one universal number—industry picked different watt anchors over time. Match the label on your equipment.

• Watt / Kilowatt: SI base units. 1 kW = 1,000 W.
• Mechanical Horsepower (hp): ≈ 745.7 W. US/UK automotive and industrial default.
• Metric Horsepower (PS, cv, hk): ≈ 735.5 W. European and Japanese car brochures.
• Electrical Horsepower: Exactly 746 W for NEMA motor nameplates.
• Boiler Horsepower: ≈ 9,810 W—steam boiler rating, not engine output.
• BTU/h: Common on furnaces and AC; 1 BTU/h ≈ 0.293 W.

Frequently Asked Questions

Is horsepower the same as torque?

No. Torque is twisting force; horsepower is how fast that work gets done over time. High torque helps towing and low-RPM pull; high horsepower helps sustained speed and quick acceleration.

Why do some cars use PS instead of HP?

PS (Pferdestärke) is metric horsepower, common on European spec sheets. One mechanical HP equals about 745.7 watts; one metric HP (PS) equals about 735.5 watts—roughly 1.5% less.

What is mechanical horsepower vs metric horsepower?

Mechanical (imperial) horsepower is the US/UK standard at about 745.7 W. Metric horsepower (PS, cv) is used in Europe and Japan at about 735.5 W. Always match the unit on the nameplate you are comparing.

How does the definition calculator work?

Enter force, distance moved, and time elapsed. The tool converts all inputs to SI base units, computes power in watts, then lists equivalent values across watt, kilowatt, and horsepower variants.

When should I use the converter instead?

Use the converter when you already know a power rating—say 150 mechanical HP on a motor plate—and need it in kilowatts or BTU/h for electrical or HVAC paperwork.