# How to Calculate Horsepower: 12 Steps

Horsepower is a unit of measurement for calculating horsepower. The term was coined by a Scottish engineer to compare the power of steam engines with the power exerted by draft horses. This article will teach you how to calculate the horsepower exerted by your car's engine, an electric motor, and your own body.

## Steps

### Part 1 of 3: Calculate Your Car's Horsepower

#### Step 1. Get the values of the torque exerted by your car

In the owner's manual look for the "technical specifications" section or from the index look for "torque", so you will find the value you are looking for. If you don't have an owner's manual, try using an internet search engine. For example, enter in the search "torque" and the make of your car, model and year. Thus, a result will emerge that works for you.

#### Step 2. Get the rotational speed of your motor, or revolutions per minute

You can also find this information in your owner's manual. If your manual does not have this information or if you do not have it, enter your car make, year and model in an Internet search engine followed by "engine speed", or simply "RPM". An online source should have this information.

#### Step 3. Multiply the torque times the turning speed

You will use the following formula: (RPM * T) / 5, 252 = HP, where RPM is the rotational speed, T is the torque, and 5, 525 is the value to convert radians per second. The first calculation you must do is multiply the torque and the turning speed.

### For example, a Porsche generates a torque of 480 to 2500 RPM. Expressed in terms of an equation it would look like this: (2,500 * 480), which equals 1,200,000

#### Step 4. Divide the product by 5250

The result would be the horsepower of your car. In the Porsche example, 1,200,000/5252 = 228.48, so the Porsche exerts 228 horsepower.

### Part 2 of 3: Calculate the horsepower of an electric motor

#### Step 1. Find the current (I), efficiency (Eff) and voltage (V) of the motor

Motor voltage is expressed in volts, current in amps, and efficiency as a percentage. The engine must have these units of measure attached.

#### Step 2. Using the following formula:

(V * I * EFF) / 746 = HP, determine the horsepower of your electric motor. Multiply the voltage, current and efficiency, then divide the product by 746. For example, the horsepower of a 230 V motor consuming 4 A and with an efficiency of 82% would be equivalent to 1 horsepower.

### Part 3 of 3: Calculate Your Own Horsepower Exerted

#### Step 1. Measure your body mass

Find out how much you weigh in kilograms and write it down. If you're using a pound scale, multiply it by 0.454 to convert it to kilograms.

#### Step 2. Find a ladder that is clear of obstructions

You'll run up the stairs on a timer, so find one that you can use without interruption.

#### Step 3. Measure the overall height of the ladder

First, measure the height of a step in meters. Then count how many steps the ladder has and multiply them by the height you measured earlier. This will give you the total height of the ladder. Write down that number.

### If your ruler is in feet, multiply the height by 0.3048 to convert the unit to meters

#### Step 4. Measure the time it takes you to run up the stairs

Start running a little before climbing the first step, as soon as your foot touches it, you will start the timer. When both of your feet are on the last step, stop the stopwatch. Write down the duration of your run in seconds. Remember, there are 60 seconds in every minute.

#### Step 5. Use the following formula:

(m * 9.81 * h) / t = HP to calculate your power in watts. In this case, m is your weight, h is the height of the ladder, 9, 81 is the gravitational constant that you must consider in the calculation and t is the time in seconds of your climb. The result you get is expressed in watts.

### For example, if you weigh 82 kg and you climb a 3.7 m high ladder in 4 seconds, that would equal: (82 * 9, 81 * 3, 7) / 4 = 744 watts

#### Step 6. Calculate your horsepower

Divide the power you got in watts by 746 to find the horsepower conversion. The result is usually between 1 and 2 horsepower.