What's The Difference Between BHP, HP, kW and PS?

Manufacturers can often pick and choose between power units, so here's a low-down of what they all equate to
What's The Difference Between BHP, HP, kW and PS?

Power units are always the headline figures associated with any new performance car and can provide interesting comparisons between cars across the entire spectrum of automotive production.

Power as an entity is a measure of how quickly and how far an engine can force the car forward, with that force being the torque produced from the internal combustion. This is generalised in engineering as the amount of ‘work’ the car has to do to propel itself along and has taken many forms since the early days of internal combustion. Generally divided into three main units used in different areas across the globe, let’s delve into what each unit of measurement means and how they compare to each other.


What's The Difference Between BHP, HP, kW and PS?

1kW = 1.341hp

Technically, this form of measurement is the most uniform method of measuring power and is used by every engineer worldwide. Watts are an SI unit (International System) which means they are based around the metre, kilogram, joule and second that make up the metric system. It is a measurement of energy transfer over time, which is the exact job that an internal combustion engine undertakes.

Used as a unit for cars mostly in the Southern Hemisphere, Kilowatts can be measured by finding the torque value from the wheels on a rolling road, followed by applying this equation:

What's The Difference Between BHP, HP, kW and PS?

Kilowatts are a modern take on car power output and I wouldn’t be surprised if it becomes the norm to use this form in Europe, although it may take a lot more to persuade Americans to make the transition.

Although considering the rise of the electric car, it would make a whole tonne of sense to start switching, as the capabilities of electric motors are measured using kWh (Kilowatt hours) which dictates how long the electric motors can produce a certain amount of power for.


What's The Difference Between BHP, HP, kW and PS?

Created by the master of the steam engine – Mr James Watt – this unit of power has somehow still survived to this day as the staple unit of power measurement of new cars where I’m from. Horsepower was deemed equivalent to a horse moving 33,000 pounds of mass one foot in one minute. Now no one knows how big this horse was or whether it was a particularly healthy horse or not…but let’s just go with it. This new-found unit allowed Watt to show direct comparisons between his steam locomotives and the common horse that dominated the haulage business up until the invention of the steam engine.

Horsepower still survives as the main power unit for us petrolheads in the UK and you lot over in the USA, staving off any outside influences from Continental Europe and Australasia. Again, this power unit can be found by a torque translation using a similar equation to that of the Watt:

It may start off as a bit of a mess, but this equation simplifies down to something very similar to that of the Watt equation
It may start off as a bit of a mess, but this equation simplifies down to…

Horsepower can become a tricky business however, with values measured in different ways. BHP (brake horsepower) refers to the equipment needed to test the engines for their power outputs, with a large drum with a water brake within it measuring the braking force once the engine is spinning at a desired rate. Over in the US, this is measured with only some ancillary components attached to the powertrain, missing things like the power steering pump which would lead to a lack of parasitic losses if in place. Therefore higher ‘HP’ figures are calculated in the US than the BHP figures calculated in Europe where every component is kept in place.

WHP or wheel-horsepower is a greater indicator of the usable power that an engine produces, as this is calculated using the exact torque that has made it through the drivetrain and is driving the wheels.


What's The Difference Between BHP, HP, kW and PS?

1PS = 0.986hp

PS stands for pferdestärke which translates simply as horsepower, but it has had some metric tweaking to try and bring good old HP forward into the 21st Century. This metric horsepower has been adopted throughout Europe as the new standard for power measurement and will probably make its way fully into the UK psyche in the not too distant future.

The official engineering standard for metric horsepower is the amount of power needed to lift a 75kg of mass one metre vertically in one second, which – once the conversions from imperial to metric are applied – equates to a 1.4 per cent higher figure than the old imperial units. Manufacturers will often pick and choose between PS and HP depending on whatever figure seems more rounded and presentable. Although I’ve always just seen PS as ‘horsepower plus a few’.

To summarise these three units of power, let’s break down famous cars and their relevant figures to put the new and old units into perspective:

Nissan Skyline GTR R34: 206kW = 276hp = 280PS (advertised)

What's The Difference Between BHP, HP, kW and PS?

McLaren 570S: 419kW = 562hp = 570PS

What's The Difference Between BHP, HP, kW and PS?

Honda Civic Type-R FK2: 228kW = 306hp = 310PS

What's The Difference Between BHP, HP, kW and PS?

Bugatti Chiron: 1,103kW = 1,479hp = 1500PS

What's The Difference Between BHP, HP, kW and PS?

What power measurement do you use? Are you an old-school horsepower fan or have you converted to the modern way of thinking with PS or even Kilowatts? Comment below with your thoughts on the matter!


Mini Madness (Group B squad)(Furrysquad)

KW then you can compare apples to apples,
rather than apples to grapes, or cider to wine.

10/01/2016 - 09:19 |
54 | 2

What’s the conversion equation for apples to grapes?

Also, quit your wine-ing…

10/01/2016 - 10:08 |
62 | 0

You can compare cider to wine though.

10/01/2016 - 12:25 |
0 | 0

How about apples to pineapples? Or apples to pen

10/01/2016 - 15:02 |
16 | 0

When I was a kid, I used to believe that in order to measure how much horsepower a car has, they would set up a tug of war (the car had to pull a rope against a certain number of horses). So HP was the maximum number of horses the car could win against…

10/01/2016 - 09:42 |
634 | 0

That….that’s amazing

10/01/2016 - 09:53 |
218 | 0

Same here :D but i always wondered how they connected 1000 horses to a bugatti 😂

10/01/2016 - 10:03 |
116 | 2

Technically you are not wrong… (as i understand it)

10/01/2016 - 15:58 |
8 | 2


10/01/2016 - 17:22 |
2 | 0
Dat muscle guy (Sam Stone)(Camaro Squad)(Die augen leader)(E

In reply to by DL🏁

I thought the same but wih donkeys instead of horses

10/01/2016 - 18:23 |
0 | 0
Zizhang Cheng

The RPM is top RPM you can drive or?

10/01/2016 - 09:50 |
0 | 0

It’s the rpm you get while getting peak torque in a specific gear

10/01/2016 - 11:10 |
2 | 0

Since you have different power and torque at different RPM the power you have at a specific RPM is related to the torque at that RPM

10/01/2016 - 13:38 |
2 | 0

The equation is actually applied continuously throughout the rev range of the engine, that’s where we get horsepower/torque or kW/torque curves. Engine power is usually described as, for example, “305 hp @ 5400 RPM and 295 ft-lb @ 3200 RPM” meaning the point where each curve is highest.

10/01/2016 - 14:46 |
8 | 0
JenstheGTIfreak (pizza)

I use PS

10/01/2016 - 10:53 |
10 | 2

Actually the Germans ignore that small difference between PS and HP, in university (in Germany of course) many teachers just said Horsepower (HP) translated to German is Pferdstärke (PS), that’s it.

10/02/2016 - 20:44 |
6 | 0
Joshua Desson

Alex’s M3 is measured in none of those. It is measured on the lemon scale

10/01/2016 - 11:58 |
76 | 0

That was savage !

10/01/2016 - 16:08 |
6 | 2

I don’t get the lemon joke..

10/04/2016 - 11:20 |
2 | 0

Why don’t we talk torque? All these measurements start with torque and torque is what really makes a difference when you are driving

10/01/2016 - 12:25 |
8 | 0

In reply to by Anonymous (not verified)

Well, that’s what a lot of people like to say, but that’s not exactly complete truth…
After all, it is the power which makes the car faster, not torque (I can feel some hate incoming, but wait)

Yes, it is the torque which results in power, which makes it a very important characteristic, but if we completely ignore the power figure then we will make things even more confusing:
For example, lets look at mk7 Golf GTD and mk7 Golf GTI. Both are identical cars, but the former has 184PS and 380Nm and the latter has 220PS and 350Nm. If we were to ignore the power, we’d think that the GTD is a faster car, but in fact the less torquey and more powerful GTI is about a second faster 0-100kmh.
So if we want it to be clear which car is faster, we need to be looking at maximum power, not the torque.

Of course, torque is still very important, and the more torque there is the more usable the power is as you don’t have to rev the engine as much to access the power. So ideally, we should be looking at two things: maximum power and the torque curve. You don’t really care what the maximum torque is, its more important that you have the torque from low revs. Also, it would be great if we could universally use kW and Nm…

10/01/2016 - 13:10 |
26 | 0
Emil Eklundh

In reply to by Anonymous (not verified)

Torque is power yes.
Kw hp and ps are measurements of power. It tells us how much work something can do.
“My car has 100nm” doesn’t tell you very much. It just means the engine can produce a force of rotation at 100nm. And watts or kilowatts tells us how much work the engine is capable of off.

04/21/2021 - 09:24 |
0 | 0

1mW = 1341 hp not 1kW

10/01/2016 - 12:37 |
2 | 4

*MW. M=mega, m=milli, very big difference (9 orders of magnitude specifically)

10/01/2016 - 13:42 |
30 | 0
Zizhang Cheng


10/01/2016 - 12:56 |
0 | 0
MikeTheMiata (MiataSquad) (MarinerSquad)

WHAT IS “BHP”!!!!????

10/01/2016 - 13:10 |
2 | 0

It’s gross HP. The power of the engine, without losses caused by drivetrain

10/01/2016 - 16:03 |
10 | 0

I still dont understand. Why? MATH!

10/01/2016 - 13:19 |
2 | 0


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