HP to kW Converter

How to Use This Calculator

1. Enter the power value.
2. Select conversion direction (HP → kW or kW → HP).
3. Click Calculate to get kilowatts, watts, and BTU/hr.
4. Use the Extended tabs for mechanical, metric, or electric horsepower variants.

Formula

Example

Frequently Asked Questions

• How many kilowatts is 1 horsepower? ▼
  1 mechanical horsepower (hp) equals exactly 745.69987 watts = 0.74569987 kW. For practical calculations, use 745.7 W or 0.7457 kW. Example: 100 HP = 74.57 kW; 200 HP = 149.14 kW; 500 HP = 372.85 kW. To convert HP to kW, multiply by 0.7457; to convert kW to HP, multiply by 1.34102 (= 1/0.7457). Common car engine power ratings: a small economy car at 90 HP = 67.1 kW; a mid-size sedan at 200 HP = 149.1 kW; a sports car at 400 HP = 298.3 kW; a supercar at 700 HP = 522 kW. Note that car ratings in Europe and Asia are sometimes given in kW on official documents, so knowing this conversion helps compare vehicles across markets.
• What is the difference between HP and PS? ▼
  There are three types of "horsepower" in common use. Mechanical HP (also called imperial or US HP) = 745.699 W — used in the US and UK for cars, engines, and most applications. Metric HP (PS, from German "Pferdestärke" = horsepower; also called cv in French and Italian) = 735.499 W — used in continental Europe for vehicle ratings. Electrical HP = 746 W exactly — used for electric motors. The difference between mechanical HP and PS is about 1.36%: 100 PS = 98.6 mechanical HP; 100 mechanical HP = 101.4 PS. When comparing European and American car power ratings, be aware that European cars rated in PS will appear slightly lower in US HP. A 100 PS Volkswagen actually produces 98.6 US HP, not exactly 100 HP.
• How do I convert kW to HP? ▼
  To convert kilowatts to mechanical horsepower, multiply by 1.34102 (= 1000/745.699). Examples: 50 kW = 67.05 HP; 100 kW = 134.10 HP; 150 kW = 201.15 HP; 200 kW = 268.20 HP; 300 kW = 402.30 HP. For metric HP (PS), multiply kW by 1.35962 (= 1000/735.499). For electric motors, divide kW by 0.746. Quick mental estimate: multiply kW by 1.34 (or roughly "add one-third" to the kW value for mechanical HP). A 100 kW electric car motor produces about 134 HP. The European New European Driving Cycle (NEDC) and WLTP test cycles express power in kW in official documents, while marketing materials often use HP for US audiences.
• How is BTU/hr related to horsepower? ▼
  1 mechanical horsepower equals 2,544.43 BTU/hr (British Thermal Units per hour). BTU/hr is the standard unit for rating heating and cooling equipment in the US: air conditioners, furnaces, heat pumps, and water heaters. A "1-ton" air conditioner removes 12,000 BTU/hr of heat = 12,000/2544 = 4.716 HP of cooling power = 3.517 kW. A 3-ton AC unit = 36,000 BTU/hr = 10.55 kW. Common air conditioning ratings: 5,000 BTU/hr (small window unit) = 1.465 kW; 24,000 BTU/hr (2-ton) = 7.034 kW; 60,000 BTU/hr (5-ton) = 17.585 kW. The BTU/hr is also used for gas appliances: a typical gas stove burner is 8,000–15,000 BTU/hr.
• How do I calculate HP from torque and RPM? ▼
  To calculate horsepower from torque (in ft·lb) and RPM: HP = (Torque × RPM) ÷ 5252. The constant 5252 comes from (33,000 ft·lb/min) ÷ (2π rad/rev) × (1 min/60 s) = 5252.11. In SI units: kW = (Torque in N·m × RPM × 2π) ÷ 60,000. Example: 300 ft·lb of torque at 4,000 RPM = (300 × 4000) ÷ 5252 = 1,200,000 ÷ 5252 = 228.5 HP. In SI: 407 N·m at 4,000 RPM = (407 × 4000 × 2π) ÷ 60,000 = 170.4 kW = 228.5 HP. The relationship shows why diesel engines (high torque at low RPM) and petrol engines (lower torque but higher RPM) can produce similar HP at different torque-RPM combinations. Peak HP and peak torque typically occur at different RPM values.

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