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What is a Power Converter?

A power converter is a digital tool designed to convert power units from one system to another. Power is a physical quantity that represents the rate of work or rate of energy transfer per unit time. In everyday life, we encounter various power units: Watt (W) for lights and home electronics, HP (horsepower) for motors and water pumps, and BTU per hour for air conditioner cooling capacity. Kalkulab's Power Converter is a practical solution for technicians, engineers, engineering students, and the general public who need to convert power units quickly and accurately. This tool supports 12+ power units including Watt (W), kilowatt (kW), megawatt (MW), horsepower (HP/PS), BTU per hour (BTU/h), foot-pound per second (ft·lb/s), and dBm.

Power Conversion Factors

1 kW = 1000 W = 1.341 HP = 1.360 PS = 3412 BTU/hFormula: 1 W = 1 J/s = 0.001 kW = 0.00134 HP

Variables:

  • 1 WWatt (W)
    SI unit for power, equivalent to 1 Joule per second (1 J/s)(e.g.: 1 W = 1 J/s)
    💡 Lights, home electronics, solar panels
  • 1 kWKilowatt (kW)
    1000 Watts, common electrical power unit(e.g.: 1 kW = 1000 W)
    💡 Home electrical power, electrical load, inverter
  • 1 HPHorsepower (HP)
    Mechanical horsepower, English/US standard(e.g.: 1 HP = 746 W)
    💡 Electric motors, water pumps, vehicles
  • 1 PSPferdestärke (PS)
    Metric horsepower, European/Japanese standard(e.g.: 1 PS = 735.5 W)
    💡 Car specifications, motorcycles, engines
  • 1 BTU/hBTU per hour
    British Thermal Unit per hour, cooling/heating capacity unit(e.g.: 1 BTU/h = 0.293 W)
    💡 AC, refrigerators, HVAC, space heaters
  • 1 dBmDecibel-milliwatt (dBm)
    Relative power unit in logarithmic scale, common in telecommunications(e.g.: 0 dBm = 1 mW)
    💡 WiFi signal, radio, telecommunications

Categories:

SI UnitsWatt and its multiples
Horsepower UnitsHP, PS, PK
HVAC UnitsBTU/h
Other UnitsdBm, foot-pound/s

How to Use the KalkuLab Power Conversion Calculator

Using the KalkuLab power conversion calculator is easy and intuitive. Follow these simple steps to convert power units:

  1. 1

    Enter Power Value

    Type the power value to convert. You can enter whole numbers or decimals (e.g., 1500 or 2.5).

  2. 2

    Select Source Unit

    Choose the starting unit: Watt (W), kilowatt (kW), megawatt (MW), horsepower (HP), PS/PK, BTU/h, dBm, or others.

  3. 3

    View Conversion Results

    Results in all power units appear automatically—no extra button needed.

  4. 4

    Use Optional Features

    Change the source unit anytime or use reset to start a new calculation.

💡 Tip:

  • •1 PK (Paardekracht) equals 1 PS = 735.5 Watts
  • •A 1 PK AC (12000 BTU/h) typically draws 800–1200 W of electricity
  • •A 5 HP electric motor equals about 3.7 kW
  • •Use a period (.) as the decimal separator

Examples

Example 1: Water Pump (HP to Watts)

Problem:

A 1.5 HP household water pump. How many Watts for electrical installation?

Solution:
  1. 1.Given: 1 HP = 746 W
  2. 2.Calculation: 1.5 HP × 746 W/HP
  3. 3.1.5 × 746 = 1119 W
Result:1119 Watts (1.12 kW)

A 1.5 HP pump needs about 1100–1200 Watts. Ensure your home wiring can handle this load.

Example 2: AC Capacity (BTU/h to kW)

Problem:

A 24000 BTU/h (2 PK) living room AC. What is the cooling capacity in kW?

Solution:
  1. 1.Given: 1 BTU/h = 0.000293 kW
  2. 2.24000 × 0.000293 = 7.03 kW
Result:7.03 kW (thermal)

A 2 PK AC has 7 kW thermal cooling capacity. Actual electricity draw is about 2–2.5 kW depending on EER.

Example 3: Industrial Motor (kW to HP)

Problem:

A 15 kW factory motor. What is the HP rating?

Solution:
  1. 1.Given: 1 kW = 1.341 HP
  2. 2.15 × 1.341 = 20.12 HP
Result:20.12 HP

A 15 kW motor equals about 20 HP. Motors are often rated in HP in countries using British/US standards.

Example 4: Home LED Lighting (Watts to kW)

Problem:

10 LED bulbs at 9 W, 5 at 18 W, and 2 at 36 W. Total power in kW?

Solution:
  1. 1.9 W: 10 × 9 = 90 W
  2. 2.18 W: 5 × 18 = 90 W
  3. 3.36 W: 2 × 36 = 72 W
  4. 4.Total: 252 W = 0.252 kW
Result:252 Watts = 0.252 kW

Total lighting is only 0.25 kW—very efficient compared to incandescent bulbs.

Example 5: WiFi Signal (dBm to Watts)

Problem:

A router outputs 20 dBm. What is the transmit power in Watts?

Solution:
  1. 1.P(W) = 0.001 × 10^(dBm/10)
  2. 2.P = 0.001 × 10² = 0.1 W
Result:0.1 Watt (100 mW)

20 dBm equals 0.1 W transmit power—enough to cover a two-story brick home.

Frequently Asked Questions

What is the difference between HP (horsepower) and PS (Pferdestärke)?
HP is the British/US standard at 746 Watts. PS is the European/Japanese metric standard at 735.5 Watts. European and Japanese cars use PS (or PK in Indonesia), while US cars use HP. 1 HP ≈ 1.014 PS.
Why is AC capacity measured in BTU/h but electricity in Watts?
BTU/h measures cooling capacity (heat moved), while Watts measure electricity consumption. A 12000 BTU/h AC only draws about 800–1200 W because it works like a heat pump, not a direct cooling heater.
What is the relationship between power (Watts) and energy (kWh) and electricity bills?
Power (Watts) is the rate of energy use; energy (kWh) is power × time. A 100 W lamp on for 10 hours uses 100 W × 10 h = 1 kWh. Electricity bills are charged per kWh.
How much power does a 1 PK AC need?
1 PK (Paardekracht) = 735.5 W for the motor. For AC, 1 PK cooling capacity (12000 BTU/h) draws about 800–1200 W depending on efficiency (EER/SEER). Higher EER means lower electricity use.
Why is dBm used in telecommunications?
dBm uses a logarithmic scale that simplifies signal chain calculations. 0 dBm = 1 mW, 10 dBm = 10 mW, 20 dBm = 100 mW, 30 dBm = 1 W. The log scale makes gain/loss easier in radio and fiber networks.
How do I choose generator size based on Watts?
Generators should be 20–30% above total load. If home load is 3000 W (3 kW), choose a 4–5 kW generator to handle motor and AC startup (inrush) current, which can be 3–5× normal power.
What is a ton of refrigeration (TR) for industrial AC?
1 TR = 12000 BTU/h = 3.517 kW—the cooling needed to freeze 1 ton of water into ice in 24 hours. Used for industrial AC, cold storage, and refrigeration plants.
How do I calculate electric motor operating cost?
Cost = Power (kW) × operating hours × electricity rate. A 5 kW motor running 8 h/day = 40 kWh/day. At $0.10/kWh, daily cost = $4.00; monthly (30 days) ≈ $120.

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References