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

Power units show up everywhere from light bulbs to jet engines

When you buy a light bulb, it's rated in watts. A generator is quoted in kilowatts or kilovolt-amperes. A car engine is described in horsepower. An industrial pump spec might use both kW and HP. Air conditioners are sold in tonnes of refrigeration or BTU/hour. These are all measuring the same thing — the rate of energy transfer — but the units vary wildly depending on the industry and the country.

A power converter handles all of these instantly. Whether you're comparing appliances, sizing electrical equipment, or decoding an engineering spec, it translates between any power unit in seconds.

Power Units Explained

Power is the rate at which energy is used or transferred — energy per unit time. The SI unit is the watt (W).

Metric units

Mechanical and customary units

How to Use the Power Converter on sadiqbd.com

1. Enter the power value.
2. Select the source unit — watts, kW, HP, BTU/hr, tonnes of refrigeration, etc.
3. Select the target unit.
4. Read the result — instant.

Real-World Examples

Sizing a generator

You need to power these appliances during a load shedding:

• Refrigerator: 150W
• 3 ceiling fans: 3 × 75W = 225W
• 6 LED lights: 6 × 10W = 60W
• Router: 15W
• Total: 450W = 0.45 kW

With a 20% safety margin: 450 × 1.2 = 540W. A 650W or 1 kW generator covers this comfortably. Generators are often rated in kVA — for a resistive load, kVA ≈ kW. For mixed loads with motors, multiply kW by 1.25 to get the kVA requirement.

Understanding car engine power

A car engine is rated at 120 bhp (brake horsepower). In kilowatts: 120 hp × 0.7457 = 89.5 kW

The same engine in metric horsepower (PS, used in European specs): 120 hp (mechanical) ÷ 0.9863 = 121.7 PS

This is why European and American horsepower figures for the same car are often slightly different — they're using different definitions of horsepower.

Air conditioner sizing

A 1.5-tonne AC is rated at 1.5 TR. In watts: 1.5 × 3,517 = 5,275.5 W = 5.28 kW

In BTU/hour: 1.5 TR × 12,000 BTU/hr per TR = 18,000 BTU/hr

This is why 1.5-tonne ACs are sometimes marketed as "18,000 BTU" units in international specs. For electricity cost calculation, what matters is the compressor's input power (typically 1.2–1.8 kW for a 1.5-tonne unit) — not the cooling capacity.

Solar panel output

A 400W solar panel in Bangladesh receives about 4.5 peak sun hours per day.

Daily energy output: 400W × 4.5 h = 1,800 Wh = 1.8 kWh Monthly: 1.8 × 30 = 54 kWh

At ৳8/kWh: 54 × 8 = ৳432/month saved per panel under good conditions.

Industrial pump specification

A pump is rated at 7.5 HP. The control panel is sized in kW. 7.5 HP × 0.7457 = 5.59 kW

The control panel needs to handle at least 5.6 kW — specify a 7.5 kW panel for safety margin.

Power vs. Energy: The Distinction Worth Making

Power and energy are related but different:

• Power = rate of energy use (watts, kW, HP)
• Energy = power × time (watt-hours, kWh, joules)

A 2 kW heater running for 3 hours uses 6 kWh of energy. Your electricity bill charges for energy (kWh), not power (kW). The power rating tells you how fast energy is consumed; the bill tells you how much was consumed over a billing period.

Tips for Working With Power Units

For electrical appliances, power in watts is on the label. Every appliance sold in Bangladesh has a wattage rating on its label or in the manual. Sum up the watts of everything you want to run to size generators, inverters, or solar systems.

HP varies by definition — always check which one. Mechanical HP (745.7W) is standard in the US. Metric HP or PS (735.5W) is used in European automotive specs. The difference is small (~1.4%) but shows up when comparing international spec sheets.

Ton of refrigeration vs. input power. The "tonnes" on an AC refers to cooling capacity (1 TR = 12,000 BTU/hr of heat removal), not electrical consumption. A 2-tonne AC might draw 2–3 kW of input power. These are different things — the converter handles the cooling capacity unit; the actual electricity draw is on the specification sheet.

Megawatts and gigawatts are for power plants. A 500 MW power plant generates 500,000 kW. Bangladesh's total installed power capacity is in the gigawatt range. These units are rarely relevant outside energy industry discussions.

Frequently Asked Questions

What's the difference between kW and kVA? kW (kilowatts) is real power — the actual work done. kVA (kilovolt-amperes) is apparent power — what the electrical supply must deliver. The ratio between them is the power factor (usually 0.8–1.0 for most equipment). For purely resistive loads, kW = kVA. For motors and inductive loads, kVA > kW.

Is 1 HP the same everywhere? No. Mechanical HP (745.7W) is standard in the US. Metric HP or PS (735.5W) is used in German, French, and much European automotive specs. Electrical HP (746W exactly) is used in motor specifications. The differences are small but matter for precision calculations.

How many watts in a kilowatt? 1 kW = 1,000 W exactly.

What does 1 ton of refrigeration mean? It's the cooling power needed to melt one short ton (2,000 lb) of ice in 24 hours. 1 TR = 3,517 W = 12,000 BTU/hr. It's a historical unit that stuck in the HVAC industry.

Is the power converter free? Yes — free, no sign-up needed.

Power ratings appear on every appliance, in every engineering spec, and in every energy discussion. Understanding the units — and being able to convert between them — is genuinely practical, whether you're sizing a generator for load shedding, comparing car engines, or planning a solar installation.

Try the Power Converter free at sadiqbd.com — instant conversion between watts, kW, HP, BTU/hr, and more.