Difference Between BHP and Torque

Physics is a subject which can easily fascinate a science lover and also question. Being a tricky subject, Physics tends to baffle and perplex us. One can get lost in confusion if the terms in Physics are not completely understood. One such confusion is BHP and Torque. Although, both are useful in measuring force they are fundamentally different.  

BHP vs Torque

The main difference between BHP and Torque is that BHP stands for Brake Horsepower and is a unit to measure the power of an engine neglecting the noise and heat loss, on the other hand, Torque is defined as the magnitude of force measured from the axis of rotation.   

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BHP or Brake Horsepower is considered as the total output of the engine in the terms of a car. It is also referred to as the rate at which work is done. It is a sub-type and modification of Horsepower measured by a brake type load- dynamometer. Horsepower is the output of an engine including the noise and heat losses.  

Torque, on the other hand, is the moment of force or rotational force. Force in linear motion is replaced by Torque in Rotational Motion. It is also referred to as the rotation of force or mass about an axis. In terms of a vehicle; it is considered as the ability of the vehicle to turn around.   

Comparison Table Between BHP and Torque

Parameters of Comparison BHP    Torque  
Invented/ Discovered By   James Watt  Archimedes  
Formula   (Torque×RPM)/5252  RPM-Rotations Per Minute) R×F or RFsintheta  
Symbol    BHP/ HP    Tau (Greek Letter) or M- Moment of Force  
Unit   Watt or J/s- Joules Per Second  Newton-meter (N-m)  
Measured By    Dynamometer    Torque Meter  

What is BHP?  

Aforementioned, BHP or Brake Horsepower determines the output of an engine overlooking the heat losses. It originated from Horsepower but is more efficient than Horsepower as HP determines output including all the losses. Brake Horsepower manifests to be essential in the brake system of a vehicle.   

In terms of a car, BHP calculates peculiarly the Horsepower of the engine of the car, excluding the gearbox and generator loss. Usually, in Horsepower, torque is measured with a torque converter, whereas, in Brake Horsepower no auxiliary tools are required to measure the torque, hence BHP is considered to be more efficient than HP. SI unit of BHP is Watt or Kilo-watt.  

Brakes are a specially designed segment of an automobile that provides braking force equivalent to the load of the automobile to maintain it at a particular rotational speed. Thus, BHP is also referred to as the Braking Power of an automobile. BHP is highly specific and is measured from a particular location in the automobile such as the Rear axle, Rear wheel, Crankshaft, Output Shaft, etc. BHP in bikes is similar to BHP in cars. In bikes, BHP is calculated as the torque generated transmitted to the wheels. High transmission leads to high BHP.   

If an automobile shows low BHP that means it can pull off heavy load, on the other hand, if it shows high BHP that means it can travel and accelerate faster. In the former American standards, BHP was referred to as Gross Horsepower which signifies their calculation and test without additional components, whereas in current American standards, it is referred to as Net Horsepower which denotes that it tests including all the additional components.   

Testing of BHP in a car is extremely simple and can be done in two ways with the right components, one way is to run the engine on a testbed, another one is to run the car on a rolling road and calculate the power transmitted to the wheels. Nevertheless, nowadays BHP is extremely useful in understanding automobiles.  

What is Torque?  

As mentioned above, Torque in simple terms is a rotational force and is a 3-dimensional force, and is usually calculated for a rigid body. The Moment of Inertia in Torque is equivalent to Mass in Force. In technical terms, torque is defined as the cross-product of position vector and force vector.   

Torque is also defined as the resultant moment of a couple or the rotation around the perpendicular axis. In layman’s terms, torque indicates the capacity of an automobile to turn on a curved road. The SI unit of Torque is Newton-meter, although The United States Torque is referred to as Inch-pound or Foot Pound.  

Torque and Pseudo Force are responsible for the outward pull we feel in a twisted and curled road, or the backward pull we feel when the vehicle is accelerating. It is essential to understand the concept of torque to understand the banking of road and well of death.   

In terms of automobiles especially cars and bikes, high torque denotes the high capacity to carry the load while low torque signifies that the vehicle can travel faster. Torque is typically measured using a Torque Meter (Transducer used for torque measurement) or Torque Converter, but varying Torque output is easily measured with the help of a dynamometer.  

Typically, Steam Engines and Electric Motors have the maximum torque, so that they can carry enough freight, on the other hand, certain bikes have the lowest torque so that they can accelerate at lightning speed.   

Main Differences Between BHP and Torque  

  1. BHP is used to calculate the power output of an engine, while Torque is the rotational force of the wheels of an automobile.   
  2. BHP is used to measure the peak speed while Torque signifies the ability to carry the load and accelerate.   
  3. SI unit of BHP is Watt or J/s whereas SI unit of Torque is Newton-meter.  
  4. BHP is location specific and is calculated from a single location, in contrast, Torque is non-specific .
  5. BHP is a derived quantity that is derived from RPM (Rotations per minute) and torque, while Torque is a fundamental physical quantity.   
  6. BHP can be calculated with the help of Torque but cannot be measured individually while Torque can be measured.   
  7. The Dimensional Formula of BHP is M1L2T-3  on the other hand, the dimensional formula of Torque is M1L2T-2 .


From the above-mentioned points, it is clear that although BHP and Torque are interconnected and dependent on each other they are intrinsically different and they carry certain remarkable differences that are unavoidable. There are several parameters through which automobiles can be compared, but BHP and Torque are mechanical terminologies that are significant.  

For an automobile to work well mechanically and technically BHP and Torque, both are essential. In a vehicle, if both Torque and BHP are equal then it denotes that the vehicle will have tremendous speed. Nevertheless, both BHP and Torque are beneficial in understanding the vehicle while purchasing them.   


  1. https://link.springer.com/chapter/10.1007/978-1-4615-3594-2_4 
  2. https://meridian.allenpress.com/rct/article-abstract/42/4/1014/87981 
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