Mostly useful for print stylesheets. On screens it seems to be defined as a constant 96px[1], which means it has no correspondence to physical inches.

[1]: https://hacks.mozilla.org/2013/09/css-length-explained/

But the CSS spec suggests around 1/96th of an inch for the size of a CSS pixel. So if you squint hard enough it kind of works out.

Welcome back to HNC News. Tonight's top story: US law makers have introduced a new bill that would require all digital displays in the United States to feature a pixel density of 96 ppi. White house officials say the new bill represents "the first step on the march to bring freedom to the cyber world". More on this after the break.

Anchor: "Let's bring in a Congressman who agreed to comment on this extraordinary turn of events"

Congressman: "I'm glad to support the expansion of freedom to all realms. Thankfully, it is now safe for us to do this that we can defend ourselves against the dangerous 'cypherpunks'. Thank you to everyone who has helped make this possible"

Ah, but since the retina iPhone, a CSS pixel != a screen pixel

I would scream from my office. Almost no one would understand my pain.

But it would make screens great again! Especially retina screens.

Screens around the world are sold based on diagonal inches. USA! USA!

As a European whose only familiarity with inches is that "it's about 3cm" that actually annoys me.

Back when screens were small it sort of worked, I knew what 13", 15", 17" and 20" screens looked like. Since most monitors fell in that range (yeah, I'm showing my age) that was good enough. Anything bigger than that was "damn huge", anything smaller was "damn small".

But now monitors and especially TVs are immense. I see TVs with diagonals of 30", 55", 65"... That means absolutely nothing to me. I have to convert into centimeters for it to make sense. Fortunately some resellers do put the metric measurement next to the inches, but not everybody does it.

If it makes you feel any better, I'm from the US and the unit is kinda meaningless. It's not like I can visualize 42" (without converting to feet first), and because it's the diagonal length it makes it basically impossible to visualize - I have to have seen it to know anyway.

Hah! Yeah I hadn't even noticed that I do this too.

I'm writing this on a 42" display, it was sold as a "TV" but it's just a dumb display as far as I'm concerned, so cheap 1080p monitor really.

Everything bigger than 42" is, in my mind, just unnecessarily big as you have to sit progressively further away from the display to comfortably watch motion pictures.

So, from my perspective, huge displays are what you need for unnecessarily huge houses.

In Japanese, they don’t translate “55"” normally, instead it becomes a “55 unit” TV. FWIW, as an American, the diagonal is unhelpful, so you need to look up the horizontal and vertical measurements anyway to know what will fit on your shelf.

Depends where you are, in France typically inches are used almost only for phones & laptop screens. Anything above (like TV) tend to use centimeters.