What Is Horsepower & Why It's A Dumb Unit - America vs Metric


What is the difference between HP, CV, PS, and kW? Why is horsepower a dumb unit?
Horsepower vs Torque - A Simple Explanation: nolocal.info/have/video/ql-BfJisy22vz5A
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Horsepower is a unit of power created by James Watt in the 1700's. Who knew all these years later we'd still be using a unit he developed to compare steam engines to horsepower. We'll go through Watt's back of the napkin math, discuss in simple terms what horsepower means, and look at metric horsepower as well: PS, CV, and the many other abbreviations. Whether metric or imperial, horsepower as a unit makes no sense at all. We'll wrap up the video learning what unit we should actually be using.
Related Links:
Derivation of HP - aapt.scitation.org/doi/10.1119/1.1999088
HP vs PS vs CV - www.autoweek.com/news/technology/a1820831/what-ps-metric-horsepower-autoweek-explains/
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  • Gary Paisley
    Gary Paisley3 dager siden

    You've never ridden a horse?

  • x1lencex
    x1lencex4 dager siden

    Actually we use kw in europe alongside hp. And when you are ordering parts, they always ask you how many kw is your engine

  • Nick S
    Nick S6 dager siden

    Boats that take outboard engines routinely have both HP and KW stamped on their manufacturer plate, so KW is not unknown in the boating world....

  • Mocanu Octavian43
    Mocanu Octavian436 dager siden

    I use hp and nm because they are more accurate

  • Eric Ozbun
    Eric Ozbun7 dager siden

    In Italy your car's registration paperwork has the car's power expressed in Kw, and every document states power in Kw ;)

  • Adrian Untalan
    Adrian Untalan7 dager siden

    Watt invented the horsepower unit... The irony is still fresh years after learning it in school.

  • Adrian Untalan
    Adrian Untalan7 dager siden

    When you actually have to do complex calculations, the simplicity of derived Metric units like *"Watt"* definitely simplifies things a great deal. You never have to memorize anything and you can usually get by with logical analysis.

  • Tristan Laing
    Tristan Laing10 dager siden

    What about BHP - break horse power - seen it in UK magazines like "practical classics". What's that about?

  • svendsen1111
    svendsen111110 dager siden

    @Engineering Explained - at the very end: “Thank you so much for WATTching” ... i see what you did there! Informative video that makes me learn, as always. Hope you are well. Cheers from Denmark

  • Andrew Sharicz
    Andrew Sharicz10 dager siden

    Oh man the light bulb is such a bad example to use....and a CF bulb at that. I guess it's the best of what there is to relate to.

  • Simon Prescott
    Simon Prescott10 dager siden

    So one kw is a Belgian draft horse? Or a stallion??

  • ACPushkin
    ACPushkin11 dager siden

    A little known historic fact is, that the unit 'Watt' was not named after James Watt himself, but instead was named after his paternal grandmother. If you want to find out more about that, just google 'wat grandma' :-)

  • D V
    D V11 dager siden

    I think it was just a prank and we all took it seriously

  • farmerallis
    farmerallis12 dager siden

    Agricultural tractors outside the US use kW as their power rating.

  • Apis4
    Apis412 dager siden

    We use Kilowatts for engines here in Australia, though it is also acceptable to use HP or BHP, but officially, it is Kw. And it does make much more sense. Horses are not factory made die cast replicants, each the same as the last, they're living breathing creatures, and there's as much variation as with people. A Shetland Pony is not going to have as power as an average horse, like a Cutting horse, or Thoroughbred or Saddler, a Danish Drum Horse or a Clydesdale is going to have more, and outliers, like the legendary early 20th century race horse, Phar Lap, are going to be freaks worth three horses. Ok, we can take an average, but what if you live in a world where there is NOT the average? What if you're Icelandic and only know your local long haired shaggy little Icelandic Ponies? What if you're Turkmeni and only know Turkomans? A hundred horse power to Halfjur is not going to sound that impressive, but to Murgunhri it'll sound like you're lying, nothing can be that powerful. OK, we have better communication today, and so people kind of know, it's established... and at least Watt had a reason... well a better reason than whichever English King Edward it was that decided to make a system of measures of three dried barley corns.... but how could you stick with it these days? Kw integrate in to the metric system, and the metric system is scaled to the planet, indexed to the speed the of light. In other words, it's based in the reality of our physical universe. Horse power is based on Watt having to communicate with people who, for the most part, assumed anything not yet explained, was the work of God or Satan, and put Cocaine and Opiates in baby food. Just saying.

  • al Zollinger
    al Zollinger13 dager siden

    nonsense brilliantly explained. Watt using HP to define Watt himself. a horse is a horse of course, or what?

  • Noctilent
    Noctilent13 dager siden

    Here's what I don't get: Does horsepower directly relate to acceleration? It seems like torque would actually tell you how fast you could accelerate because its the actual force you're accelerating the car with, F=ma. Tell me if this is correct: Two engines, same amount of torque over their operating range, but the NA one has twice the horsepower of the turbo one. Wouldn't they be capable of the same acceleration, just the NA will be at twice the RPM?

  • dom toredo
    dom toredo15 dager siden

    11:50 i just lost control on myself and laughed as loud as i can when you said "one horse could have more than 1 horse power".

  • Vlad Soare
    Vlad Soare15 dager siden

    The thing is, when we look at the technical specs of a new car, we don't really care what its power output means in engineering terms. We just need to know how it compares to other cars that we can relate to. For most people the power of their engines has no absolute meaning, it only has a relative one - i.e. their own car vs. other cars. And for this purpose horsepower is perfectly adequate. Watts and kilowatts make perfect sense in engineering, but not so much in real life. Not for the average Joe anyway. If you told me that my car had a maximum power output of 333 kW, that would mean absolutely nothing to me, whereas 450 HP tells me that it's faster than my buddy's 400 HP, and noticeably slower than a 600 HP Ferrari - which at the end of the day is what I actually want to know.

  • I'm cool
    I'm cool16 dager siden

    I like abstract units of measurement. Trade secrets and all that stuff.

  • actionjksn
    actionjksn16 dager siden

    I don't care if it makes no sense this is America and we're sticking with horsepower. Plus it actually does make sense we know what a 300 horsepower or a 400 horsepower engine can do.

  • Skeptical Caveman
    Skeptical Caveman16 dager siden

    The hypocrisy of him continuing using horsepower after he admitted that it made no sense. He want it changed but fights the change by sticking to tradition, so irrational.

  • Eugene
    Eugene17 dager siden

    Apparently 1 horse can actually produce around 15hp. A typical human can produce around 1hp. The original base unit was hopelessly underestimated.

  • Redtooth 75

    Redtooth 75

    14 dager siden

    An average horse can output 1 horsepower continuously throughout the day, but can produce about 15 horsepower for a short period of time.

  • Mr. Mac
    Mr. Mac17 dager siden

    this means that this whole mumbo jumbo was done on an imaginary no of what a horse can pull, different horse can pull different so it was a averaged no of 180

  • keijo kokamägi
    keijo kokamägi18 dager siden

    Actually here in Europe we use kW, when talking about cars, nobody uses here hp or ps. Exept Finnish, they use hp's for some reason 😀

  • Pablo Schless
    Pablo Schless18 dager siden

    Engine Horsepower Rating is ALSO different because of different standards for measuring it. Some standards DELETE the power consumption of accessory drives (water pumps, hydraulic pumps, fuel pumps etc). Some Standards take actual power output of Flywheel. And do not give 'credits' for accessory drive power consumption.

  • johnnybro13
    johnnybro1318 dager siden

    Horsepower is fun tho

  • B Y
    B Y19 dager siden

    I'm surprised to learn that CV is Italian. I was always told the Renault CV2 literally meant 2 horse power.

  • Stu McCabe
    Stu McCabe19 dager siden

    I never knew there was a metric horsepower! I'm English and I always use 745.7 in my calculations (actually I ususlly just use 750 which is close enough!) PS I like the horsepower as a unit of power - it's relatable to human experience like feet, incense and yards.

  • pdd
    pdd19 dager siden

    Thanks for watting.

  • Jeremy Villalobos
    Jeremy Villalobos20 dager siden

    It would have been useful to discuss the Joule and the Newton on the way to the big reveal.

  • Speedox 12
    Speedox 1220 dager siden

    Conclusion: we can use horsepower to describe lightbulb power. I will now describe my computer in terms of horsepower.

  • Common Tater
    Common Tater20 dager siden

    Now do a video on when to use pound-feet vs foot-pounds.

  • Barac Vinko
    Barac Vinko20 dager siden

    My God Soo booooriing

  • smokeldogg
    smokeldogg21 dag siden

    My LS1 Trans Am was listed at 300hp and blew everything away.

  • shuaibvp
    shuaibvp23 dager siden

    No ones going to talk about his horse drawing ?

  • Burnt Chicken Nugget
    Burnt Chicken Nugget23 dager siden

    I allways thought horsepower was weird. Somtimes some cars are faster with less. Murica make me angy.

  • Kenji Biscop
    Kenji Biscop24 dager siden

    A horse has 2.5-10 horsepower I know it doesn´t make sense but it is what it is

  • Phillip Morrison
    Phillip Morrison26 dager siden

    It is funny that you say American use units that dont make any since, but the whole video is about how other countries use the same unit but convert it wrong.

  • Kevin Pascual
    Kevin Pascual26 dager siden

    Watt are you talking about???

  • adriano venrooj
    adriano venrooj26 dager siden

    The US are just to big and lazy to convert to anything. They still think the world should adapt to them. The only other country that officially uses the imperial system is Liberia. Liberia is what their president would call a shithole country.

  • Chinmay Jadhav
    Chinmay Jadhav27 dager siden

    Watt an informative video

  • Brian
    Brian27 dager siden

    Conclusion: freedom units is basically napkin maths

  • Theo Zimmermann
    Theo Zimmermann28 dager siden

    As an engineer I'm getting scared seeing someone using units and formula symbols in one equation. And what the heck is "lbf" and "kgf"? I mean I get it, but is this a real thing in the US? I'm a metric engineer in automotive in Germany and I have never ever came across that. But thank you for that explanation where a horsepower actually comes from. I'll implement this in my lectures.

  • Theo Zimmermann

    Theo Zimmermann

    14 dager siden

    @Redtooth 75 yeah, when I said "I get it", then I meant that I get it... but thanks for that unnecessary explanation. I just don't understand why the US hates the metric system so much. Why not using N as the rest of the world. There's no need to measure things in bold eagles per square freedom.

  • Redtooth 75

    Redtooth 75

    14 dager siden

    Lbf is pounds-force, it is used to signify that pounds is being used as a unit of force and not mass. One pound (mass) exerts one pound-force due to gravity. Its the same for kgf, although the standard unit is newtons. One kgf is the force 1 kg mass exerts due to earth's gravity, 9.807 newtons.

  • SergioWrites
    SergioWrites29 dager siden

    Okay so how exactly do you test the kilowatts of a car?

  • Liam Sweeney
    Liam Sweeney29 dager siden

    Who says it was back of the napkin maths? He could've carried out experiments to figure out the average power of a horse and we might not know about them

  • Euthyphro
    EuthyphroMåned siden

    Fun fact. The average horse can put out up to 15 horsepower. Humans can output up to about 5 horsepower.

  • Mihai Mera
    Mihai MeraMåned siden

    I'll start telling people that my light bulbs are 20 milihorse power

  • Tychohuybers
    TychohuybersMåned siden

    I'm sorry but "kilograms force" makes my ears bleed.

  • hunati31
    hunati31Måned siden

    You need better mike. You're welcome.

  • hunati31
    hunati31Måned siden

    My car has tigerpower.

  • TheRobbiUno
    TheRobbiUnoMåned siden

    Isn’t the Murican HP actually the Imperial HP?

  • Bruno Ethier
    Bruno EthierMåned siden

    Well yeah, like all american outdated units the hp should die. 94% of the earth's population use metric. 😏

  • F4RD4D0 PFAL762
    F4RD4D0 PFAL762Måned siden

    Is Just me that thinks It, or the imperic system is actually ridiculous?

  • Lemon Checks
    Lemon ChecksMåned siden

    awesome ideas, how-to and delivery. 1 *attaboy* for your sir. not 5.73 attaboys.. just 1 ; )

  • Mojo Neko
    Mojo NekoMåned siden

    Hi I would like to see you do a video on the difference between "Continuous Shaft Horsepower" used for diesel engines and "Peak Horsepower" used for automotive engines. Thanks for all the interesting videos!

  • Jacob
    JacobMåned siden

    None of this matters at all anyways.

  • Carbon Crank
    Carbon CrankMåned siden

    as usual... he's full of gobbledygook.

  • thetommantom
    thetommantomMåned siden

    Was this engine lifting weight tested

  • thetommantom
    thetommantomMåned siden

    What is work overtime? Something I will not do

  • L Barbato
    L BarbatoMåned siden

    Why the US doesn’t go metric says it all, weird indeed, suffer stupids.

  • L Barbato

    L Barbato

    Måned siden

    @Richard Bossman Aus converted to metric back round 1972. As I started an engineering trade that year it was a major concern for me that I knew nothing about the metric system. However, in my first calculation lesson of 1 1/2 hrs I learnt the whole metric system, it’s that easy, it made my life so much easier. All measuring tools, engineering drawings etc etc we’re slowly phased out when requiring replacing / renewing not a total change over night, phasing out. The imperial system is caveman stuff my friend.

  • Richard Bossman

    Richard Bossman

    Måned siden

    When you are the best you don’t have to be like the rest. That aside you have no idea how much it would actually cost to convert the U.S. over to metric.

  • Armin Garmrudi
    Armin GarmrudiMåned siden

    in persian we call it اسب بخار meaning steam horse, from steam engine and horse power.

  • Dave B
    Dave BMåned siden

    *I base all mu car purchases off how much flour they can mill. Gotta have my bread*

  • TryAdaptLearn
    TryAdaptLearnMåned siden

    With more Evs and hybrids Kw could be a good option. Hopefully additional marketing will include torque and vehicle weight as as much as they market hp and mpg. All four values would help to combine the ideas of efficiency and performance as a means to the same goals, like you have with many of your videos.

  • Tigger0067
    Tigger0067Måned siden

    Relax dude..haha

  • charlie McCutcheon
    charlie McCutcheonMåned siden

    1:11 did anyone else think 3 inch plumbing flashing for roofing?

  • Admranger
    AdmrangerMåned siden

    Just remember, there are two types of countries; those that use the metric system and the one that has landed a man on the moon and safely returned him (multiple times). Ha! That being said I wish the US would go to the metric system. Easier maths.

  • Drew Northup

    Drew Northup

    2 dager siden

    When we sent men to the moon we did it in metric. Everything was converted to/from "customary" USA units for interaction with the astronauts, but the computers used metric internally.

  • SuperNiCoNaTeR
    SuperNiCoNaTeRMåned siden

    About 6 months ago I discovered that there was something fishy about the horsepower unit. I was trying to figure out a way to solve it but no one I know thinks math is actually fun. Everyone thought I was crazy. I’m so glad to see someone is Shedding light on this One thing that does not make sense to me is how come the horsepower and torque always cross at 5252. I understand the math but it does not seem realistic. For example if a diesel engine cannot rev to 5252 then the cross cannot show up so why should it be set in stone that a dino cross at 5252. I understand how a Dino works and that there are multiple kinds of dinos. I feel like instead of using one unit to find another unit we should find both units independently I wish I knew more people with the hobby of questioning the things we use I need to do more research

  • Redtooth 75

    Redtooth 75

    Måned siden

    Horsepower cannot be measured directly, only calculated. The formula when torque is in ft*lb is (torque X RPM)/5252. When the rpm is equal to 5252 horsepower and torque have the same value. If an engine cant rev to 5252 rpm, torque and horsepower will never be equal to each other. The lines crossing is meaningless, its just because of the units used. If you measured torque, speed, or power with different units then the lines would cross at different points.

  • Bararara Bororor
    Bararara BorororMåned siden

    Very useful video, i switched to metric and now my car has 5 more horsepower 👍

  • Stjepan Matić
    Stjepan MatićMåned siden

    I want him so hard to start swearing

  • Imran A
    Imran AMåned siden

    No wonder motorcycles are fast. They're like the same size as a horse, weigh more, but have more hp

  • Imran A
    Imran AMåned siden

    Don't worry man. If I ever make my car (hopefully), I'll name the power by the watt

  • Evan Lichtenhan
    Evan LichtenhanMåned siden

    So in conclusion, we should start referring to light bulbs by their horsepower?

  • Jan Svoboda
    Jan SvobodaMåned siden

    Actually, here in Europe, you get often description of power for engines in both HP and kW side by side.

  • Ali Syed
    Ali SyedMåned siden

    Whenever I hear hp, I do quick mental math to work out the Watts cuz it's just so intuitivell

  • Lou F
    Lou FMåned siden

    1 horse power 5 men 3,000,000 ants 5 horses to 1 elephant

  • Performance Blue Over You
    Performance Blue Over YouMåned siden


  • TheFMCFG
    TheFMCFGMåned siden

    But Jason, how many horses can I replace with my 110kW car?

  • Rastislav Straka
    Rastislav StrakaMåned siden

    Personally i am so familiar with rating of power of cars in killowats that when somebody says it in Horsepower, i need to calculate it back to kW to know what the hell they are talking about.

  • Tulmar
    TulmarMåned siden

    I guess it was the force needed to turn the big heavy millstone that the wheel was attached to. This may be related to a standard size of millstone used at the time. Just a guess.

  • JoManOut
    JoManOutMåned siden

    My car has 112,750 Ft. Lbs. A second of power

  • Bob Webb
    Bob WebbMåned siden

    I think the pit pony was pulling up a load from a mine. Not spinning a stone. So 180lb was measured weight.

  • MrSaemichlaus
    MrSaemichlausMåned siden

    R . O . A . S . T . E . D .

  • MrSaemichlaus
    MrSaemichlausMåned siden

    Me, a European: What the heck is kgf? We don't do that here. We use N for Newton. Remember, metric is easy. You just need to forget your traumatic experiences of living in America and let your mind be at ease.

  • utah wanderlust700
    utah wanderlust700Måned siden

    How many kilowatts does the 812 Superfast have then?

  • Quentin L
    Quentin LMåned siden

    Actually in ur diagram the “horse” is pulling the weight from the saddle horn. Oh hahaha no... the weight must be tied to the tail

  • infamouselixir 90
    infamouselixir 90Måned siden

    Power to weight ratio is a more accurate depiction of how a car will accelerate a car could have 300hp but weigh 3 tonnes yet a 100hp car that weighs 1 tonne will accelerate very similar. I think. May be wrong but that’s how I have always worked it out when deciding what cars to buy. 200hp per tonne is the sweet starting point of fun in my opinion

  • Nishad Abdulkhader
    Nishad AbdulkhaderMåned siden

    Great and smacky explanation...hats off

  • Kayyos Kd
    Kayyos KdMåned siden

    k 🙂..

  • Kayyos Kd
    Kayyos KdMåned siden

    Next video, Minicar drive test..? Lol

  • MrEshah
    MrEshahMåned siden

    Quick snippet out of wikipedia - "Most countries now use the SI unit watt for measurement of power. With the implementation of the EU Directive 80/181/EEC on 1 January 2010, the use of horsepower in the EU is permitted only as a supplementary unit.[3]" also apparently usain bolt produced a maximum of 3.5hp when setting his 100 metre dash record.

  • Ariel Goodman
    Ariel GoodmanMåned siden

    I hope he trademarked his logo, volvo's rear lights resemble his logo.

  • musicwelikemang
    musicwelikemangMåned siden

    Killerwasps are the only way to measure my engine. It will destroy ponies.

  • Ben W
    Ben WMåned siden

    I heard on Mars you can only use the hamsterpower unit.

  • chinmay garg
    chinmay gargMåned siden

    Isnt power equals force multiplied by velocity? Force multiplied by distance is work done.

  • Sacto1654
    Sacto1654Måned siden

    You could make engines express their output in KW but even in Europe, some people are still confused by what that means. Interestingly, people better understand the kilonewtons (kN) used to measure engine thrust from jet engines and rockets.

  • Simply Static
    Simply StaticMåned siden

    So basically... South Africa's math makes more sense 🤣 (we use metric and base all our cars on KW for eg. A 120hp car is ~88kw)

  • Paul Makinson
    Paul MakinsonMåned siden

    Who cares how many horsepower a car is if it is a donkey driving it.

  • Mark J
    Mark JMåned siden

    Would if it was called Squirrel Might? Or Whale Thrust? We should switch to CowPower. 🐄

  • yash jadhav
    yash jadhavMåned siden

    why is he using force as a unit force is not a unit newton is a unit force

  • Redtooth 75

    Redtooth 75

    Måned siden

    So if kgf