We all need relief when we want to compare the performance of different vehicles, which is why there is a power-to-weight ratio calculator. The following text will explain how to calculate the power-to-weight ratio and why you need it so much.

Don’t hesitate to visit other interesting posts from the physics section. But also, make sure to see other related sections, such as statistics and this related Central Limit Theorem, or Probability of 3 Events calculator.

What is the power-to-weight ratio calculator? Definition

A power-to-weight ratio calculator is a calculation commonly applied to engines and mobile power sources that allows one unit or design to be compared. The PWR calculator measures the actual specifications of any engine. Calculators are also used as a measurement specification for a vehicle or vehicle complete with engine power, divided by the weight or mass of the vehicle, giving measurement data that are independent of vehicle size.

How to calculate the power-to-weight ratio?

The contact or ratio of strength and weight will be most easily explained through the example of cycling. Suppose we have two bikes; one bike can consume 250w of power and the other only 240w; both cyclists will race in the race to the top of the climb. The question is, who will win the race to the top? From a logical point of view, when we calculate it, it will be like this; the winner will be a bike from 250w of power in a race. But, not if the cyclist on that bike weighs 100kg and the other cyclist weighs 75kg. This is because it is difficult to carry more weightiness uphill. It’s the same with engines. More potent engines have more power than weaker ones, but it’s harder to carry their weight in these conditions.

Power to Weight illustration. Girl is driving a bike.

Therefore, the PWR calculator helps assess real-world conditions and obstacles performance.

Calculation of power-to-weight ratio

Before explaining the calculation of the PWR, it should be mentioned that the typical unit of measure of the PWR is W kg.                                                            

The designation we use for engine power is (P), regarding the power produced by the engine is divided by its weight (W). P- toward – W = P/W We will give a classic instance for a V-8 turbocharged engine that can have a 250 horsepower engine and can weigh 450 kg (1000 Ib) which gives a power of 0.42 kW (0.25 horsepower / Ib) It is important to note that, in most cases, we can use a calculator to calculate the vehicle’s power without the weight of the person or some other load. However, this can lead us to deviations about motorcycles and bicycles because the rider himself can have 1/3 to 1/2 the weight of the vehicle itself.

Chart of power-to-weight ratio

EnginePower-to-weight ratioTotal output power
Space Shuttle – Turbo engine100 horsepower / lb / 164,120 W / kg70,000 horsepower / 52,198kw
V8 Diesel engine with turbo0.25 horsepower / lb / 410 W / kg250 horsepower / 186.42 kW
Boeing 777 GE90-115B jet engine6.10 horsepower / lb / 10,041 W / kg111,526 horsepower / 83,164kw

Examples of calculating the power-to-weight ratio

PMR is defined as follows:

PMR = (Pn / mt) × 1,000 kg / kW

The power-to-mass ratio index (PMR) is used to calculate acceleration.

The basic unit to calculate the power-to-weight ratio is \frac{w}{kg} equal to \frac{m^2 }{s^3}

This fact allows the display of the power-to-weight ratio using the SI unit. The ratio of power and speed of vehicles, planes, rockets, and others is equal to the acceleration multiplied by the speed.

Best power-to-weight ratios

Recently, more and more manufacturers are offering better and more efficient motor-powered products. As a result, people are increasingly interested in vehicles or transports with an excellent PWR calculator. Below is an exemplar of a vehicle with an excellent PWR:

Two-stroke engines have the best power-to-weight ratio calculator, motorcycle engines, and motorboats with low power up to – 5 horsepower.

They are easy to operate, lightweight allow you to carry them without outside help. Moreover, engines are economical and have low fuel consumption.

Increasing the power-to-weight ratio

We will take a simple example of a horse, the average horse that is strong one horsepower can lift one object that weighs 75 kg in 60 minutes and pull it for 1 minute. More recently, we have said that it has replaced the metric system. We express power in W, apropos in kw. When we convert these values the ratio will be as follows: 1horse power = 0.735 kW or 1Kw = 1.35962 hp

Since we live in the age of motor vehicles, and we have used them the most throughout the text, we will also explain how they increase the power-to-weight ratio calculator. The “torque” plays a vital role in increasing strength and weight, and it is equal to the product of the force and the distance of the place where that force acts. The force you use is denoted by the unit Nm “torque.”

We will increase the PWR ratio calculator with the help of torque, which is engine speed. The higher the engine speed, the higher the amount of fuel burned, and therefore we get a higher power ratio.

Simply, more revs – more power.            

Significance of power-to-weight ratio calculator

The importance of the power-to-weight ratio calculators is crucial to us to determine or know how an engine will behave at a given moment, how much speed it will develop about its weight, whether it is good or bad for our needs, whether it will be strong enough to the mass to be carried, pulled and similar. A power-to-weight ratio calculator can facilitate several calculations.


What is power-to-weight ratio?

The power-to-weight ratio is the natural characteristic of a motor vehicle. It is used by dividing the power of one engine by the mass it carries and drives.

Why is the PWR ratio calculator good for us?

PWR calculator helps assess the power of an engine or drive about what we need and whether it will meet our needs in the given conditions. In addition, the calculator gives us complete privacy to calculate the power-to-weight ratio for everything we need.

How is the PWR calculated? Formula

The power-to-weight ratio is calculated by dividing the power of an engine or starter by its total weight and the weight it carries under given conditions.

Formula: P- toward – W = \frac{P}{V}

What is the significance of the PWR ratio calculator?

The significance of the power-to-weight ratio calculator is that it can predict performance quite accurately and calculate the power-to-weight ratio under special conditions in certain places.