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Power Converter

Energy & Power

Convert power units instantly — watts, kilowatts, mechanical and metric horsepower, BTU/hr. Ideal for motors, generators, and appliance ratings.

Reviewed by the thecalcu.com team · Last updated June 14, 2026

From
To
All conversionsfor 1 Kilowatts (kW)
Watts (W)1000
Kilowatts (kW)1
Megawatts (MW)0.001
Gigawatts (GW)0.000001
Horsepower — Mechanical (hp)1.3410221
Horsepower — Metric (PS / CV)1.3596216
BTU per Hour (BTU/hr)3412.1416
Calories per Second (cal/s)239.00574

What is a Power?

A Power Converter translates a power rating between the unit systems used in electrical engineering, mechanical engineering, and thermal science, watts, kilowatts, megawatts, gigawatts, mechanical horsepower, metric horsepower (PS/CV), BTU per hour, and calories per second.

Power is the rate of energy transfer or conversion. One watt equals one joule per second. Every power unit is a different way of expressing that same rate, reflecting the historical and technical contexts in which it was defined.

In India, power units appear across multiple contexts simultaneously. Car brochures quote engine output in bhp (brake horsepower) and kW. Industrial electric motors are rated in both kW and hp. Air conditioner cooling capacity is stated in tonnes of refrigeration (1 TR = 3.517 kW = 12,000 BTU/hr). Solar panel and inverter specifications use watts and kilowatts. Grid-scale renewable energy capacity is measured in megawatts and gigawatts.

The coexistence of metric and imperial specifications creates practical confusion. A 150 bhp car engine, how many kW is that? A 2-tonne commercial AC rated at 24,000 BTU/hr, how many kW of cooling does that deliver? These are everyday questions for engineers, technicians, and consumers, and this converter answers them instantly.

For energy (power consumed over time), see the Energy Converter. For vehicle fuel consumption, see the Fuel Efficiency Converter.

Why Use a Power Converter?

The most common pain points this converter resolves:

  • Car buying: Indian car brochures list peak power in bhp and kW side by side, but importers and automotive media mix hp (mechanical) with PS (metric). A 2020 European press release might quote 200 PS; the Indian brochure says 197 bhp, both refer to the same engine via a 1.4% rounding difference.
  • AC sizing: HVAC engineers and homeowners need to cross-reference BTU/hr cooling ratings with electrical input power in kW to calculate running costs at ₹6–9 per unit.
  • Industrial motors: BIS-rated motors in India carry both kW and hp labels. Procurement teams regularly need to confirm that a 10 hp motor = 7.46 kW for switchgear and cable sizing.
  • Solar installations: Solar panel arrays and inverters are rated in kW (peak), and comparing with diesel generator output in kVA requires converting to kW first.

Who Should Use This Converter?

Automotive enthusiasts and car buyers comparing power outputs across international and Indian-spec cars, where bhp, PS, and kW appear interchangeably in reviews and brochures.

HVAC engineers and AC technicians sizing air conditioning systems where cooling capacity in BTU/hr must be related to electrical load in kW for circuit breaker and cabling specifications.

Electrical engineers and industrial electricians selecting motors, generators, and inverters that carry dual kW/hp ratings per BIS standards.

Solar energy installers and EPC contractors converting panel array peak power (kWp) to running output estimations and comparing with grid or diesel backup in kW or kVA.

Physics and engineering students working across problems that use watts (SI), horsepower (mechanical engineering), and BTU/hr (thermodynamics) in the same course. Pair with the Energy Converter for energy-over-time calculations.

What Insights Does the Power Converter Give You?

The primary output shows your entered power rating in the chosen target unit with full decimal precision, 100 kW renders as exactly 134.102 hp (mechanical) or 135.962 PS (metric).

The reference table shows all 8 units simultaneously. For a 1.5-tonne AC rated at 18,000 BTU/hr, the reference row immediately shows: 5,275.3 W, 5.275 kW, 7.077 hp, 7.173 PS, 4,500 cal/s, a complete cross-system picture.

Practical benchmarks:

  • < 1 kW: small appliances, LED lighting, fans
  • 1–10 kW: air conditioners, water heaters, EV onboard chargers
  • 10–100 kW: commercial HVAC, small industrial motors, light EVs
  • 100 kW – 1 MW: industrial plant equipment, large generators
  • 1 MW+: utility-scale power systems, data centres, wind turbines

How to use this Power calculator

  1. Select your source unit from the FROM dropdown, e.g. Kilowatts (kW).
  2. Enter your numeric value, e.g. 150 for a 150 kW engine.
  3. Select your target unit from the TO dropdown, e.g. Horsepower, Mechanical (hp).
  4. The result appears instantly, 150 kW = 201.15 hp.
  5. Use the ⇅ swap button to flip FROM and TO with one click.
  6. Check the reference table to see the power rating in all 8 units at once.
  7. Share or bookmark the URL, it preserves your entered values.

Formula & Methodology

All units convert to and from watts (W) using exact multipliers:

| Unit | Symbol | Watts (toBase) |
|---|---|---|
| Watt | W | 1 (base) |
| Kilowatt | kW | 1,000 |
| Megawatt | MW | 1,000,000 |
| Gigawatt | GW | 1,000,000,000 |
| Horsepower (mechanical) | hp | 745.69987158 |
| Horsepower (metric) | PS / CV | 735.49875 |
| BTU per hour | BTU/hr | 0.29307107 |
| Calorie per second | cal/s | 4.184 |

Conversion formula: Result = Input × (F_from ÷ F_to)

Derivation of mechanical horsepower:
1 hp = 550 ft·lbf/s = 550 × 1.3558179483 J/s = 745.69987 W (using exact ft and lbf definitions)

Derivation of metric horsepower:
1 PS = 75 kgf·m/s = 75 × 9.80665 N·m/s = 735.49875 W (using standard gravity, exact)

Worked example, engine power comparison:

A Maruti Suzuki Swift petrol engine is rated at 89.7 kW. What is this in bhp and PS?

bhp (mechanical) = 89.7 ÷ 0.74570 = 120.3 bhp PS (metric)      = 89.7 ÷ 0.73550 = 121.9 PS

The brochure rounds to 121.4 bhp, within the expected rounding tolerance.

Common power reference values:

| Device / System | Power |
|---|---|
| LED bulb | 8–12 W |
| Ceiling fan | 50–75 W |
| 1.5-tonne split AC | ~1,200–1,500 W |
| Average car engine (India) | 60–120 kW |
| Small wind turbine | 1–10 kW |
| Large solar farm unit | 1–500 MW |

Frequently Asked Questions

A power converter (in the unit-conversion sense) is a tool that translates a power rating from one unit to another, such as from kilowatts (kW) to mechanical horsepower (hp) or from BTU per hour (BTU/hr) to watts (W). Power is the rate at which energy is consumed or produced, and it is expressed in different units depending on whether the context is electrical, mechanical, or thermal. This converter covers all major power units in a single step.
Mechanical horsepower (hp), used in the United States and the United Kingdom, is defined as exactly 550 foot-pounds per second, equal to 745.69987 watts. Metric horsepower (PS in German, CV in French/Spanish) is defined as 75 kilogram-force metres per second, equal to exactly 735.49875 watts. The difference is about 1.4%, a 100 hp (mechanical) engine produces roughly 101.4 PS. Indian car manufacturers typically quote mechanical horsepower (bhp) in their specifications.
BHP stands for brake horsepower, the power measured at the engine's output shaft using a dynamometer (brake), before accounting for drivetrain losses. It is numerically the same unit as mechanical horsepower (1 bhp = 745.70 W) but specifies where the measurement was taken. Most Indian car brochures quote bhp figures, which represent the engine's gross output. Wheel horsepower (whp), measured at the driven wheels, is always lower due to transmission and differential losses.
To convert kilowatts to mechanical horsepower, divide by 0.74570 (or multiply by 1.34102). For example, 100 kW = 100 ÷ 0.74570 = 134.1 hp. To convert to metric horsepower (PS), divide by 0.73550 (or multiply by 1.35962). A 100 kW electric car motor is equivalent to roughly 134 bhp, a figure that appears frequently in Indian EV launch press releases.
Multiply BTU/hr by 0.29307 to get watts. For example, a 12,000 BTU/hr air conditioner draws approximately 12,000 × 0.29307 = 3,517 W = 3.517 kW of cooling power. Note that this is the cooling capacity, not the electrical power consumption, efficiency (COP or EER) determines how many watts of electricity are needed to deliver that cooling.
Indian air conditioners use two ratings: the cooling capacity in BTU/hr (or tonnes of refrigeration, 1 TR = 12,000 BTU/hr = 3.517 kW), and the electrical input power in watts or kW. The BEE star label on Indian ACs shows ISEER (Indian Seasonal Energy Efficiency Ratio) = cooling output (BTU/hr) ÷ power input (W). A 5-star 1.5-tonne AC typically has an ISEER of 5.0–5.9, consuming around 1,000–1,200 W of electricity.
A gigawatt (GW) is one billion watts (10⁹ W) or one million kilowatts. It is the unit used to describe national power grid capacity and large power stations. India's total installed electricity generation capacity exceeds 900 GW as of 2025. A single large nuclear reactor generates about 1 GW. The memorable pop-culture reference is the 1.21 GW required by the DeLorean time machine in Back to the Future, a figure that roughly matches a modern nuclear plant's output.
Select your source unit from the FROM dropdown, for example, 'Kilowatts (kW)'. Enter your value, such as 150 for a car engine rated at 150 kW. Choose the target unit in the TO dropdown, such as 'Horsepower, Mechanical (hp)'. The result appears instantly: 150 kW = 201.2 hp. Use the ⇅ swap button to reverse the direction, and check the reference table below to see the rating in all 8 units simultaneously.
For mechanical horsepower: hp = W ÷ 745.69987. For metric horsepower (PS): PS = W ÷ 735.49875. These conversion factors come from the exact definitions of each unit, 1 mechanical hp = 550 ft·lbf/s = 745.69987 W (using exact mile and pound definitions); 1 metric hp = 75 kgf·m/s = 75 × 9.80665 = 735.49875 W. The converter uses these exact values, not rounded approximations.
Electric motors used in industrial and agricultural applications in India are rated in both kilowatts (kW) and horsepower (hp), with IS 325 standardising induction motor ratings. Common ratings are 0.37 kW (0.5 hp), 0.75 kW (1 hp), 1.5 kW (2 hp), 3.7 kW (5 hp), and 7.5 kW (10 hp). Agricultural pump sets are commonly specified in horsepower by Indian farmers, while power utilities and engineering firms use kW in their documentation.
A watt is a joule of energy per second, the SI unit of power. In everyday terms: a standard LED bulb uses 8–12 W, an electric ceiling fan uses 50–75 W, a desktop computer uses 200–400 W, a microwave oven uses 800–1,200 W, and a 1.5-tonne split AC uses about 1,200–1,500 W. The total power draw of your home determines the sanctioned load in kW on your DISCOM electricity connection, typically 1 kW for a small household to 10 kW for a large commercial premises.
Power (in kW) × Time (in hours) = Energy (in kWh). If a 2 kW water heater runs for 1.5 hours, it consumes 3 kWh (3 units). At ₹6 per unit, that costs ₹18. Your DISCOM electricity bill totals all kWh consumed across all appliances over the billing period (usually monthly). See the [Energy Converter](/energy-converter/) to translate kWh into joules or BTU for cross-context comparisons.
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