Power-to-Weight Ratio Calculator
Calculate the power-to-weight ratio to assess performance. Enter power and weight, select their units, and compute the ratio in W/kg or hp/lb. Supports standard, step-by-step, and chart views.
Result
Calculation Steps
Power and Weight Comparison
Formula
Power-to-Weight Ratio Calculation
The power-to-weight ratio is calculated as:
Where:
- PWR: Power-to-Weight Ratio (e.g., W/kg, hp/lb)
- Power: Power output (e.g., mW, W, kW, MW, GW, hp)
- Weight: Mass or weight (e.g., µg, mg, g, kg, lb)
Usage Notes:
- Power and weight are converted to consistent units (W and kg or hp and lb) before calculation.
- All inputs must be positive numbers.
- Results are rounded to 3 decimal places.
- Key conversions: 1 hp (imperial) = 745.7 W, 1 hp (metric) = 735.5 W, 1 lb = 0.453592 kg.
How to Use the Power-to-Weight Ratio Calculator
- Input Values: Enter power and weight values.
- Select Units: Choose appropriate units for power and weight.
- Choose Output Unit: Select W/kg or hp/lb for the result.
- Choose Display: Select standard, step-by-step, or chart view.
- Calculate: Click “Calculate” to process inputs.
- View Results: Review the power-to-weight ratio and visualizations.
- Reset: Click “Reset” to clear fields.
Frequently Asked Questions (FAQs)
What is a Power-to-Weight Ratio?
The power-to-weight ratio measures a vehicle’s performance by dividing its power output by its weight, indicating how much power is available per unit of weight.
Why is power-to-weight ratio important?
It’s a key indicator of acceleration and performance, allowing fair comparisons between vehicles of different sizes, such as cars, motorcycles, or even theoretical objects.
What are typical power-to-weight ratios?
Economy cars: ~0.05–0.1 hp/lb (~80–250 W/kg); sports cars: ~0.15–0.35 hp/lb (~250–550 W/kg); motorcycles: often >0.4 hp/lb (>600 W/kg).
What is curb weight?
Curb weight is the total weight of a vehicle with standard equipment, full fuel, and fluids, but without passengers, driver, or cargo. It’s used for consistent power-to-weight calculations.
How does power-to-weight ratio affect performance?
Vehicles with higher ratios accelerate faster and perform better in dynamic situations, as they have more power to move each unit of weight.