Power Unit kW to hp Converter

Convert power between kilowatt and horsepower with expert accuracy. Pick mechanical metric electrical or boiler definitions. Control rounding and significant figures. See formulas and working. Use reverse mode. Fast reliable converter for engineers students and makers. Supports unit prefixes and precision options.

Input
If converting from hp enter a value in that selected standard.
Permalink
Results
kW
1
hp (mechanical)
1.341
Quantity Value
kW1
hp (mechanical)1.341
hp (metric PS)1.36
hp (electrical)1.34
hp (boiler)0.102
Tip: change rounding settings to suit your specification or reporting standard.

2. Understanding Kilowatts (kW) and Horsepower (HP)

What is a kilowatt? A kilowatt (kW) equals 1,000 watts. One watt is one joule of work per second. You’ll see kW on utility bills, on electric vehicle spec sheets, and on motor nameplates (especially for larger motors). Because the kilowatt is SI‑based, it plays nicely with other metric units like newton‑meters (torque) and joules (energy).

What is horsepower? Horsepower (HP) originated as a way to compare steam engines to horse teams. It expresses mechanical output power. Over time, different definitions emerged. Two common ones you’ll encounter are:

  • Mechanical horsepower (also called imperial horsepower): used widely in North America; 1 kW = 1.34102209 hp.
  • Metric horsepower (PS) from the German “Pferdestärke”: used in many automotive contexts; 1 kW = 1.35962162 PS.

Because both HP variants are still common, a good converter lets you select which one you need—and clearly labels results as hp (mechanical) or PS (metric). Our calculator does exactly that.

Formulas

Core definitions:

  • 1 hpmechanical = 0.745699871582 kW
  • 1 hpmetric = 0.73549875 kW
  • 1 hpelectrical = 0.746 kW
  • 1 hpboiler = 9.8095 kW

Conversions:


kW → hp (chosen standard):   hp = kW / kW_per_hp
hp → kW (chosen standard):   kW = hp × kW_per_hp

Note: Standards differ slightly by definition, so values vary by context such as automotive, electrical, or steam boiler ratings.

Examples
  1. 100 kW to hp (mechanical): 100 ÷ 0.74569987158227 ≈ 134.102 hp
  2. 250 hp (metric) to kW: 250 × 0.73549875 = 183.875 kW

Use the permalink to share your specific setup and results.

Unit notes
  • Mechanical hp: common for engine output in many countries.
  • Metric hp (PS): used historically in Europe and Asia for vehicle power.
  • Electrical hp: based on exactly 746 W per hp.
  • Boiler hp: steam-generation rating; not comparable to engine hp.

FAQs

Mechanical horsepower is defined as 745.699871582 W per hp while metric horsepower PS is 735.49875 W per hp. The two are close but not identical.

hp = kW ÷ kW per hp for the chosen standard. For example with mechanical horsepower hp = kW ÷ 0.745699871582.

Yes. Use kW = hp × kW per hp for the selected standard. Set the quantity to "hp → kW" and choose the appropriate standard.

Different fields historically defined horsepower using slightly different watt equivalents. The calculator shows all standards so you can pick the correct one for your application.

Use enough precision to meet your spec or reporting rules. Engineering summaries often use 2–3 decimals while technical analysis may use 4–6 decimals or significant figures.

No. Boiler horsepower is a steam-generation measure used for boiler output. Use mechanical or metric horsepower for engines and motors and electrical horsepower for electrical machinery.

Yes. Use the Copy button to place the full table on your clipboard and use the Permalink to share a link with all inputs and rounding settings.

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