1. What is Power to Weight Ratio?

The Power to Weight Ratio (PWR) is a calculation commonly applied to engines and mobile power sources to compare the performance of different vehicles or machines. It's equal to the power output divided by the weight of the vehicle or machine.

2. How Does the Calculator Work?

The calculator uses the simple formula:

Where:

• \( kW \) — Power output in kilowatts
• \( Weight \) — Weight in kilograms

Explanation: The ratio gives you the amount of power available per unit of weight, which is a key performance metric in vehicles and machinery.

3. Importance of Power to Weight Ratio

Details: A higher power-to-weight ratio indicates a better performance potential, as the engine has more power to move each unit of weight. This is crucial in automotive design, aerospace, and competitive racing.

4. Using the Calculator

Tips: Enter the power output in kilowatts (kW) and the weight in kilograms (kg). Both values must be greater than zero for the calculation to work.

5. Frequently Asked Questions (FAQ)

Q1: What is a good power-to-weight ratio for a car?
A: For passenger cars, 0.08 kW/kg is decent, while performance cars may exceed 0.15 kW/kg. Race cars often have ratios above 0.25 kW/kg.

Q2: How does this compare to horsepower per ton?
A: 1 kW/kg is approximately 1.34 hp/kg. To convert to hp/ton, multiply the kW/kg result by 1340.

Q3: Why use kW instead of horsepower?
A: kW is the SI unit of power and is increasingly used in international specifications, though horsepower remains common in some regions.

Q4: Does this apply to electric vehicles?
A: Yes, the concept is equally valid for electric vehicles, though their power delivery characteristics differ from combustion engines.

Q5: How accurate does this need to be for comparisons?
A: For meaningful comparisons, use consistent measurement standards (e.g., always use manufacturer's stated power or always use dyno-measured power).