Horsepower is not horsepower. American "HP" is not the same as the horsepower (PS, pferdestärke) we use in Europe when we talk about "horsepower". a kW is always 1000 watt, not 992.3 watts because of course it's a Canadian kW.

That make me curious to look up the Koenigsegg's power. It would seem they are metric horsepower:

>Two common definitions used today are the mechanical horsepower (or imperial horsepower), which is about 745.7 watts and the metric horsepower, which is approximately 735.5 watts.

I guess speaking as a Brit the foreigners just didn't have proper horses.

Brits will have to concede to the French on that one. A French poncelet is 100kg raised one meter in one second, ~980W.

So you’re telling me I can’t even trust SI unit abbreviations when coming from beyond the pond? That a kW in America isn’t 1000 W as it should be?

F*ck :D

You think that's bad, try talking to computer people. They think a kilo of their bits means 1024 of them, not 1000!

This is wrong in Hard drive SSd manufacturers are very happy to give you 1000 bits per Kilobyte.

Computer people speak in Base 2 units because that's how the devices operate at a low level.

After many years and different widths the smallest common unit of exchange evolved to be a power of two: 8 bits are a byte, not 9, 10, 27, 30, etc; though Unicode might have been better off if 32 bits were the base character. However then older systems would have been at least 75% less useful.

Physical addressing units are also binary, because literal address lines (or their virtually latched equivalents on a serial bit-shift register) are used.

ROM, RAM, and correspondingly non-volatile writable storage inherit this basic premise.

So a non-sales computer person speaking 'kilo' or 'mega' or any other SI unit in relation to a computer part means it will hold or be able to transfer at least that many SI units in the quoted units. Everything gets rounded to the nearest useful neighbor. A digital kilo is not 1000, it is 2^10. A digital mega is correspondingly also 2^20. This is very similar to the exponents in SI units.

For that matter, humans have 8 fingers and 2 thumbs. Wouldn't an octal numbering system make more sense? Though for that we'd have to come up with new unit names near 2^3, 2^6, 2^9, etc that don't sound silly.

> For that matter, humans have 8 fingers and 2 thumbs. Wouldn't an octal numbering system make more sense? Though for that we'd have to come up with new unit names near 2^3, 2^6, 2^9, etc that don't sound silly.

Each of the 4 long fingers has 3 phalanges, so an interesting possibility is to use each thumb to count up to 12 on each hand. Given that many ancient units of measurement where base-12, I wonder why we didn't develop base-12 languages.

I've heard that's how merchants used to count in the Mediterranean. However much like QLC and TLC SSDs are more finicky to work and require stricter discipline than simple on/off storage, the same can be said for fingers and is it up or down.

Kilo is always 1000. Kibi is 1024.

https://en.wikipedia.org/wiki/Binary_prefix

Kibi didn't exist until 1998 (per your link), so anything you read that was written prior to that and for a few years after still has the kilo=1000/1024 ambiguity.

I know the 'kibibytes' thing but never encountered it in a real-world context (e.g. like "the C64 had 64 kibibytes of RAM").

I personally decided to just use them always for clarity and I saw few people around me catch on. Be the change you want to see, especially when it comes to the free minor stuff.

In the verbal context of IT, it is 1024. If you're being technical, you can nitpick and say it's wrong. Has no benefit, though.

I like!

Wish we could all start understanding the difference between kilo and kibi, mega and mebu and so on for bits and bytes.

Sometimes b is for bit and B is for byte, however, just about as often b is for byte and B is for bit.

Nah, kb means kibbibytes, not kilobytes :)

I was born 48 years ago.

The advantage is not having to remember all those funny constants and being able to do math in your head that actually makes sense?

Or more important, to be able to write an article that the entire planet can just read without 95% of them (everybody outside the US, UK and Myanmar) having to resort to Google to find out if those numbers are impressive or not?

Funny how all these proponents of SI units state their age in years instead of seconds :)

It isn't funny because the GP doesn't want SI units to be used because they are a standard but because 95% of the world can understand them. I'm certain that more than 95% of people understand years.

And some will never understand humour either

Humor also often has a lot of contextual flex, which is intentional misinterpretation (e.g., unintentional double meaning) is often humorous.

Just laugh at the joke.

Phsh, I know a guy that celebrated turning a billion seconds old. Brought pie and everything

>The advantage is not having to remember all those funny constants

This, very much! I've done a ton of physical simulation code in my life. Whenever some newb or student comes to me for the first time with their simulation code that mysteriously doesn't work, in 90% of cases they stupidly didn't stick to SI and forked up some unit conversion, or mutiple. I tell the to keep it in SI and never let me see them make that mistake again. (Only exception is simple 1-to-1 unit conversions of parameters and results, when some stupid interface definition demands it that can't easily be changed.)

I think the point was that horsepower is widely understandable and preferred in Europe as a unit of an engine power, despite otherwise using the SI units.

Horsepower is different though, you have imperial horsepower and metric horsepower (and many more). Both are not the same and neither is a round 750 watts.

For the last years I’ve mostly seen watts being used in NL, but it’s been ages since I saw a fast and furious movie or a top gear show. The car sellers use kW and often also, I assume metric, horsepower.

add Canada and you've named like a fifth or a quarter of all English speakers

Good addition / correction. So the amount of people that is unable to follow the article without too much effort went down from 95% to 80% of the audience.

The value is twofold:

1. Everything uses a common base, so you don't get a base change on a scale change (or indeed, two different bases for different parts of the same measurement), and dimensional consistency becomes trivial.

2. The base is base-10, which is the same as our common counting system.

There are two exceptions I’m aware of to “SI is easier in practice”.

1. Temperature. It’s useful to elongate units over the range normally experienced by humans, which Fahrenheit does and Celsius does not, because it avoids tenths of a degree, for example, in room temperature selection.

2. Woodworking and similar: it’s useful to use powers of two because it’s very common to be marking/cutting/etc. 1/2 or 2x a value, which is easier to do in inverse power of two English measurements.

I've found metric to be better for woodworking, and especially metalworking. Powers of two (imperial) are no easier than doubling a metric measurement, and more difficult when partitioning items items in thirds or fourths, or having to cut wood in half with lengths like 56 and 7/32 inches (1428mm).

Celsius isn't SI, though I can appreciate there are reasons for particular units in particular circumstances.

One degree Celsius is exactly the same as one Kelvin, though.

Same. Screens and wheels are still 100% described in inches in sales. Cars are specified with HP and optionally kW. Never kW alone.

Outside of these weird exceptions, it's SI all the way. And this doesn't really vary with age. The web site whrere you buy wheels and TVs doesn't know your age so it will say the rims or screens are 20" regardless of who you are.

There's more nuance to it though: if you take a closer look at fields where inch are used even in fully metric language environments you'll find that it's often more a class designation than a measurement. A 21 foot container does not exist (turns out that according to the wiki 20 foot containers aren't even allowed to be 20 foot long, they are 40/2 minus some defined amount of padding)

It's even more pronounced with camera sensors, the size given in fractions of an inch is some kind of "equivalent to", whereas the size in mm is the actual size. Apparently the image sensor inch is 16mm or something like that.

Calories, grit, carats (for diamonds), Beaufort, viscocity is of ten boven in cP, grit (based on inches), dernier, rpm, dpi, lightyears, and of course km/hr. Plenty of non-SI units in use

Yes. I meant metric and sloppily said "SI" despite most common metric units only occasionally being SI.

Beaufort is a dimensionless label as far as I'm aware and grit is used as such too (i.e. it never says anything else than "240" i.e. it doesn't "240 grit" or "240 something per inch").

Grit is based on the amount of particles that fit through an inch square. You could also indicate it with the particle size inmicrometers.

My list wasn't close to exhaustive. We use all kinds of weird units.

Besides bar I sometimes see mmHg for pressure. Shoe sizes. I've never seen acceleration in m/s2 outside a physics problem, otherwise it's either G or seconds to 100 km/hr.

> We use all kinds of weird units. > Grit is based on the amount of particles that fit through an inch square.

I'm aware. But I'd say its mostly used as a dimensionless. When I argue "we use metric except for these few" I mean in the cases where the unit (a length, mass, pressure etc) is actually uttered or written.

In some cases as you note there are labels which have non-metric definitions underneath, such as sand paper particles having a never-pronounced inch definition. The same goes for some weapon calibers where you might say a ".303 cartrige" for rifle ammunition but you'd never say a ".303 inch cartidge". A lot of people probably use these labels without knowing they are using an imperial definition. And that (I'm guessing) is also part of why it survived the metrification.

> I've never seen acceleration in m/s2 outside a physics problem, otherwise it's either G or seconds to 100 km/hr.

"10s to 100km/h" is as metric as m/s2 though (But again not pure SI). g being a constant obviously has no explicit unit, it's as metric as you want it to be :) I hear "5g" as 5x9.82m/s2 but an american probably hears something else.

Now with electric cars we have battery capacity specified in kWh, vehicle power in kW and charging capability in kW.

This is all as it should, however a large number of people have a really hard time groking the difference between kW and kWh.

So much so that I wonder if we should start specifying battery capacity in MJ to help people clarify things in their heads.

I've noticed that some EV users talk about charging rates in "kWh/h". Which is interesting, to say the least.

Someone needs to teach them algebra

most of the value is in having a uniform and consistent system of units.

It is the mixture of both that ends up being very confusing.

I don't have a mental model for "64 pounds". Apparently, it s the weight of a 9 year old, which would ve been a better unit of measure.