Power Converter — Watts, kW, Horsepower & BTU/hr

Convert electrical and mechanical power through watts—motors, HVAC, EV chargers, and grid-scale plants. Mechanical hp, metric PS, J/s, and ton cooling included.

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By Muhammad Abdullah Rauf · Founder, EverydayTools.proUpdated 2026-05-21

What is a power converter?

A power converter translates between units of power—the rate energy flows—such as watts (W), kilowatts (kW), mechanical horsepower (hp), and BTU per hour (BTU/h), without confusing them with energy totals like kWh.

Power measures how fast energy is used or delivered. In SI, the watt is one joule per second. Kilowatts label home appliances, EV chargers, and solar inverters; megawatts describe utility-scale generation; mechanical horsepower still appears on engines and motors in the US; HVAC equipment in North America is often quoted in BTU/h or nominal tons of cooling.

This tool normalizes every value through watts, then shows equivalents across all supported units at once. That is ideal when a datasheet lists hp but your spreadsheet expects kW, or when an air conditioner is rated in BTU/h but you are sizing a breaker in watts.

  • Power (W, kW, hp, BTU/h) answers “how fast?”
  • Energy (kWh, BTU, joules) answers “how much over time?”—use the energy converter when you need totals.
  • Conversions run locally in your browser; nothing you type is uploaded.

Normalize through watts: 1 hp ≈ 745.7 W, 1 kW ≈ 1.341 hp, 1 BTU/h ≈ 0.293 W—and never swap BTU/h with plain BTU (energy).

Quick answers

Concise answers for common searches — definitions, steps, and comparisons.

Is the power converter private?

Yes. Math runs entirely in your browser. Numbers you enter are not uploaded to EverydayTools servers.

How many watts in one horsepower?

1 mechanical horsepower ≈ 745.7 watts. 100 hp ≈ 74.57 kW. 1 kW ≈ 1.341 hp.

kW vs kWh—which do I need?

kW is power (rate). kWh is energy (power × time). This tool converts power only; multiply kW by hours for kWh estimates on the energy converter.

How to use Power Converter — Watts, kW, Horsepower & BTU/hr

  1. Enter a power value

    Type the number you want to convert. All listed units update together from a single watts baseline.

  2. Select the from unit

    Choose from and to units in the dropdowns (W, kW, MW, hp, PS, BTU/h, ton cooling, J/s)—or tap a grouped preset for HVAC, auto, or grid.

  3. Read the to unit and factor

    Choose the target unit under To. The highlighted row shows 1 from-unit = X to-unit for copy-paste into specs.

  4. Copy or share

    Use Copy Result for a one-line summary, or Share on supported mobile browsers. Reset returns to 1 W → kW.

Power Converter — Watts, kW, Horsepower & BTU/hr examples

Convert car engine power from hp to kW

Input

300 hp (car engine)

Output

223.7 kW · 223,710 W · 763,558 BTU/hr

European type approval uses kW; US brochures use hp. 300 × 745.7 W ≈ 223.7 kW.

Convert home appliance power for electricity cost

Input

2,000 W (electric kettle)

Output

2 kW · 2.68 hp · 6,824 BTU/hr

A 2 kW kettle for 5 minutes uses 2 kW × (5/60) hr ≈ 0.167 kWh—pair with the energy converter for bill math.

HVAC cooling capacity

Input

12,000 BTU/h (1 US ton)

Output

≈ 3,517 W · 3.52 kW

Residential AC is often quoted in BTU/h; electrical load planning needs watts or kW.

Who uses Power Converter — Watts, kW, Horsepower & BTU/hr?

Common real-world scenarios where this tool saves time.

Car buyers and automotive enthusiasts

Convert engine power between hp and kW

Compare vehicles from US/UK hp ratings with European kW figures on equal terms before buying or insuring.

Electricians and electrical engineers

Convert HVAC and appliance ratings to watts

Turn BTU/h air-conditioner labels into kW for breaker sizing, wire gauge checks, and panel load summaries.

Energy and sustainability analysts

Compare generation capacity across sources

Express wind turbines, solar inverters, and gas plants in the same MW or kW unit for portfolio comparisons.

Workflow guides

Step-by-step chains that connect related tools for common tasks.

Size a circuit from an appliance label

  1. Convert the label to watts or kW with this tool.
  2. Add other loads on the same branch.
  3. Compare to breaker and wire ampacity with your local code—this tool does not replace an electrician.

Cross-check hp and kW on an import car listing

  1. Enter horsepower from the US listing.
  2. Read kilowatts for comparison with EU brochures.
  3. Confirm whether the listing uses mechanical or metric hp before signing paperwork.

Reference tables

Common power conversion factors

Mechanical horsepower and BTU/h factors used in this tool.

UnitIn watts (W)Notes
1 W1SI base unit
1 kW1,000EV chargers, appliances
1 MW1,000,000Utility-scale plants
1 hp (mechanical)745.7US automotive / many engineering tables
1 BTU/h0.293HVAC North America
12,000 BTU/h≈ 3,517≈ 1 US ton of cooling

Metric horsepower (PS) ≈ 735.5 W—not included; convert via watts when needed.

Everyday power anchors (order-of-magnitude)

Real devices vary—use for intuition, not guaranteed draw.

Device / contextTypical power
LED bulb8–15 W
Laptop (active)30–65 W
Microwave (heating)~1 kW
Level-2 EV charger7–11 kW nameplate
Residential AC (1 ton)~3.5 kW cooling
Small car engine75–150 kW peak

Nameplate ratings are maximums; duty cycle and efficiency change real consumption.

Common mistakes to avoid

Confusing kW with kWh

kW is power; kWh is energy over time. Use this tool for rates; use the energy converter for totals.

Using BTU/h when the spec says BTU

BTU per hour is power; a plain BTU is an energy chunk—do not swap them in formulas.

Assuming marketing hp equals mechanical hp

Appliance labels may use rounded marketing hp. For engineering, work in watts or trace the datasheet.

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Frequently Asked Questions

How many watts in a horsepower?

1 mechanical horsepower (hp) = 745.7 watts. 1 metric horsepower (PS or CV) = 735.5 watts. Common values: 100 hp = 74,570 W = 74.57 kW. 1 kW = 1.341 hp (mechanical).

What is the difference between mechanical and metric horsepower?

Mechanical (imperial) horsepower: 1 hp = 745.699872 W—used in the US and UK for engine ratings. Metric horsepower (PS in German, CV in French/Spanish): 1 PS = 735.49875 W. A 200 PS car has about 197.3 mechanical hp.

How do I convert BTU/hr to watts?

1 BTU/hr = 0.29307 watts. 1 watt = 3.41214 BTU/hr. Common HVAC conversions: 6,000 BTU/hr = 1,758 W ≈ 1.76 kW. 12,000 BTU/hr (1 US ton of cooling) = 3,517 W = 3.517 kW.

How many watts does a typical home use?

Average US home electricity consumption: ~10,500 kWh/year ≈ ~1,200 watts average continuous draw. Peak demand (air conditioning, electric cooking): 5,000–10,000 W. Individual appliances: LED bulb 10 W, laptop 50 W, refrigerator 150 W, electric oven 2,000–5,000 W, electric car charger 7,200–22,000 W.

Is the horsepower in this tool the same as metric horsepower (PS)?

This converter uses mechanical horsepower ≈ 745.7 W. Metric horsepower (PS) is about 735.5 W—close for casual chat, wrong for spec sheets. When in doubt, work in watts.

How are BTU per hour and air-conditioning tons related?

Residential HVAC in the US quotes equipment in BTU/h or nominal tons. One ton of cooling is traditionally about 12,000 BTU/h. Use BTU/h here for datasheet cross-checks, not for duct design without a Manual J.

Why does my EV charger show kW while my bill talks about kWh?

The charger label is power—how fast energy flows. The utility cares about energy delivered over time (power × hours). Multiply kW by hours plugged in for kWh; use the energy converter when totals matter.

Are my inputs uploaded?

No. All math runs in your browser; nothing you type is sent to our servers.

Privacy, accuracy, and trust

Privacy

Values stay in your browser; conversions are not uploaded to EverydayTools servers.

Accuracy

Uses standard conversion factors (745.7 W per mechanical hp, 0.293071 W per BTU/h). Marketing hp on appliances may differ from mechanical hp—verify datasheets for compliance work.

Part of Unit Converters

More free tools for the same workflow.

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Reviewed by EverydayTools Editorial Team on 2026-05-21.