What those power numbers on your bike actually mean

If you’ve ever flipped through a spec sheet for a superbike, an adventure tourer or even a 125‑scooter, you’ll know manufacturers like to throw a bunch of numbers at you. Peak power, max torque, redline RPM… and tucked in there somewhere are units like bhp, hp, kW and PS. They’re all ways of saying how powerful a bike’s engine is, but the subtleties matter if you care about what the bike actually does on the road or track.

Brake Horsepower (bhp) or Horsepower (hp)

On bikes, when you see bhp quoted – say 180 bhp at 11,500 rpm on a litre bike – you’re looking at the engine’s power, usually measured at the crank. That’s the number traditional British bike mags, and a few OEMs still prefer.

A lot of people use the term “horsepower” casually, but hp on spec sheets – particularly on US‑market bikes or magazines – can mean a slightly different method of measurement. That same 180bhp converted to US-spec HP would translate to 177.5 hp.

James Watt originally coined the term “horsepower” to compare steam engines to draft horses. Bikes have long exceeded the pulling power of a team of Clydesdales by sheer revs alone, but it remains the preferred method of imagining and benchmarking the work an engine does.

Pferdestärke (PS)

If you’re reading European bike brochures, especially from Germany or Italy, you’ll often see PS instead of bhp. PS stands for Pferdestärke – literally “horse strength” in German. Functionally, it’s a version of metric horsepower.

For riders, the important bit is that one PS is roughly 0.986 of one imperial horsepower. In practice, that difference is tiny, but it explains why Ducati will list something like 158 PS while a UK mag might call it 156 bhp.

If you see CV listed against a bike, it means chevaux‑vapeur, which is French for, you guessed it, horsepower. It’s the same thing as PS, but carrying a string of onions and wearing a beret.

Kilowatts (kW)

Now here’s where engineers grin, and bike geeks squint. kW is the International System of Units (SI) measurement. One kilowatt equals 1,000 watts. It’s the unit the rest of the engineering world uses, and you’ll increasingly see it on European motorcycles’ official spec sheets alongside bhp or PS.

Why? Because it’s neutral – it doesn’t carry the baggage of steam‑era definitions. And on electric bikes and scooters, kW is becoming the default way to talk about peak power. Harley‑Davidson’s LiveWire, Zero’s range, and most other EVs list their motors’ outputs in kW because it ties directly to electrical power.

For quick conversions: 1 kW ≈ 1.34 bhp and 1 bhp ≈ 0.75 kW. So using that same 180 bhp bike, its power in kW would be 132.39 kW. As a quick reference, a learner legal machine with bang on 15bhp would come up at around 11 kW.

So What Should Riders Care About?

You see, the numbers on the page are less mysterious than they first appear – they’re just different ways of saying the same thing. But for motorcyclists, they shape how we judge a bike’s character:

bhp/PS/hp: these are peak power numbers – handy for eyeballing how a litre sportsbike stacks up against rivals. kW: the future‑proof way of measuring power, especially on electric machines and when comparing across vehicle types. And all of them are still just part of the story – real‑world acceleration and feel depend on weight, torque curve, gearing and geometry far more than a single number ever will.

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