Enter the power of your engine and the total weight of your vehicle to calculate the power-to-weight ratio (PWR).
Use this power to weight ratio calculator to understand the true performance potential of your vehicle, machine, or even yourself as a cyclist. The calculator is a helpful option for comparing the power (ability to do work) of something to its weight (mass).
The power-to-weight ratio is a measurement that helps to compare the power output of a machine (like an engine or motor) in relation to its weight. It's a key metric used to evaluate the performance of many things, including vehicles, athletes, and aircraft. Generally, a higher power-to-weight ratio indicates better acceleration and handling. It is also used by cyclists to assess their fitness level.
Here's why it's important:
By understanding PWR, you can make informed decisions when choosing equipment or training strategies to improve your cycling performance. A power-to-weight ratio calculator can be a valuable tool in this process. Keep in mind that PWR is a calculated value, and factors like friction and air resistance can affect it.
Follow these three simple steps to calculate PWR:
Determine the power output of the object or vehicle. Keep in mind that units can vary but the most common units that are used are horsepower (hp) for engines or watts (W) for motors. You can find the power output on the user manual, or product specification sheet or can search online.
Weigh your object or vehicle. Pounds (lb) or kilograms (kg) are the two common units that are used to measure weight. For vehicles, curb weight(weight of the vehicle without passengers or cargo) is used.
PWR =\(\frac{Power}{Weight}\)
Alternatively: Our power to weight ratio calculator also uses these pre-defined formulas to convert your inputs into a meaningful hp to weight ratio, so that you can have a deeper understanding of your system or vehicle's performance.
1 . Calculate the power-to-weight ratio of a car with a weight of 3,000 pounds and an engine power of 350 horsepower.
Solution:
Given that:
By adding values in the power-to-weight ratio (PWR) formula:
=\(\frac{350}{3000}\)
= 0.11667 (hp(l)/lb)
2. Find power to weight ratio of a cyclist who weighs 60 kg and can sustain a power output of 210 watts.
Solution:
Given that:
Put values in the power-to-weight ratio formula:
=\(\frac{210}{60}\) = 3.5 W/Kg
To quickly get the PWR values, use the power to weight calculator.
Weight | 120W | 150W | 180W | 210W | 240W | 270W | 300W | 330W | 360W | 390W |
45kg | 2.7 | 3.3 | 4.0 | 4.7 | 5.3 | 6.0 | 6.7 | 7.3 | 8.0 | 8.7 |
50kg | 2.4 | 3.0 | 3.6 | 3.8 | 4.8 | 5.4 | 6.0 | 6.6 | 7.2 | 7.8 |
55kg | 2.2 | 2.7 | 3.3 | 3.5 | 4.4 | 4.9 | 5.4 | 6.0 | 6.5 | 7.1 |
60kg | 2.0 | 2.5 | 3.0 | 3.2 | 4.0 | 4.5 | 5.0 | 5.5 | 6.0 | 6.5 |
65kg | 1.8 | 2.3 | 2.8 | 3.0 | 3.7 | 4.1 | 4.6 | 5.0 | 5.5 | 6.0 |
70kg | 1.7 | 2.1 | 2.6 | 2.8 | 3.4 | 3.8 | 4.3 | 4.7 | 5.1 | 5.6 |
75kg | 1.6 | 2.0 | 2.4 | 2.6 | 3.2 | 3.6 | 4.0 | 4.4 | 4,8 | 5.2 |
80kg | 1.5 | 1.9 | 2.2 | 2.5 | 3.0 | 3.4 | 3.8 | 4.1 | 4.5 | 4.9 |
85kg | 1.4 | 1.8 | 2.1 | 2.3 | 2.8 | 3.2 | 3.5 | 3.9 | 4.2 | 4.6 |
90kg | 1.3 | 1.7 | 2.0 | 2.2 | 2.7 | 3.0 | 3.3 | 3.7 | 4.0 | 4.3 |
95kg | 1.2 | 1.5 | 1.9 | 2.0 | 2.5 | 2.8 | 3.2 | 3.5 | 3.8 | 4.1 |
It depends on the specific application and motor design. However, permanent magnet motors are generally considered to have the highest power-to-weight ratio because of their high torque, density, and relatively lightweight construction.
The car power to weight ratio helps to know how fast a car can accelerate. While PWR is a crucial factor, it's not the only thing that determines acceleration.
References:
From the source of Wikipedia: Power-to-weight ratio, Physical interpretation, Propulsive power
From the source of Jteach.org: Calculating Power to Weight Ratio, When Performance Matters