This is STILL NOT WORKING. It's not fair for you guys to mark this as COMPLETED when it's not fixed. 100% view is inaccurate, even with the Display Print Size checked.

Still broken in most recent release. Pasting previous comment here for posterity:

This does not work on my existing monitor (at my workplace), but it did work on the previous one.
It should be noted that the previous monitor was detected by Windows 10 for what it was (some flavor of Dell ultrasharp, no longer in production) and the current one (a 32in LG, not sure of the model) is only detected as "Generic PnP Monitor". UI scaling in the OS doesn't seem to have much affect. Mine is set to 125%, otherwise everything is way to small to see comfortably.

At present, with OS UI scaling at 125%, 100% print view in illustrator makes a 1" box display at 1.125".
Using OS UI scaling at 100%, the same 1" box displays at 1.25" in illustrator.

This was not a problem with the previous monitor.

Print size should influence only documents designed for print!
Now, if you create 100×100px rectangle, using Web profile, you'll have something like 136×136px actual size (screenshot it and measure in PS).
Of course you can enable Pixel Preview to see it in true 100%, or disable the Print Size, but this is just wrong.

Thanks for pointing this out. This was driving me crazy. screencaps brought into Illustrator was a completely different scale and was messing up my workflow so much. Thanks.

For print work this is very cool but for web work it's a disaster. This feature needs to be automatically disabled if the document units are set to pixels. Otherwise we can't see what our designs will look like on a screen!

This does not work on my existing monitor (at my workplace), but it did work on the previous one.
It should be noted that the previous monitor was detected by Windows 10 for what it was (some flavor of Dell ultrasharp, no longer in production) and the current one (a 32in LG, not sure of the model) is only detected as "Generic PnP Monitor". UI scaling in the OS doesn't seem to have much affect. Mine is set to 125%, otherwise everything is way to small to see comfortably.

At present, with OS UI scaling at 125%, 100% print view in illustrator makes a 1" box display at 1.125".
Using OS UI scaling at 100%, the same 1" box displays at 1.25" in illustrator.

This was not a problem with the previous monitor.

This does not work on Surfaced Pro 7. 1 inch (on screen ruler) is showing as 2.5 inches when " Display Print Size at 100% Zoom" is set

I agree with this future improvement. For each type of LCD screen it differs. There should be something like a wizzerd in the preference/option box.

I just tested 100% on my monitor and was pleasantly surprised that an A4 sheet was automatically exactly the right size.

This works great for me:

I zoom to 138.89 because "my screen dpi(100)" x 0.72 = ~138.9

Create a new View by going to "View" > "New View..."

Set a shortcut for the new view (custom view 1) and DONE!

Tip: I used "Ctrl + ." (numpad dot) because ctrl+1 is 100% size, ctrl+0 is artboard size, and now ctrl+. is real life size and I have all shortcuts close to each other so I can easily switch between them...

Hope it helped!

This feature would be great. I don't know how much I'd use it but it would hopefully get rid of the madness that is the AI 2019 true-size feature, where "actual size" is only actually true on your primary monitor. (See https://illustrator.uservoice.com/forums/601447-illustrator-bugs/suggestions/35743504-actual-size-view-menu-does-not-display-at-actual-s)

However this feature is implemented, I'd recommend a textbox so people can put in a floating-point ppi number (or related number) if they want to be exact.

This would be genius if you can make it happen. I do all my own illustrating, and it would save TONS of time when I import into FrameMaker if I could work with illustrations that fit exactly into 42 picas!!

The sad thing is, CS6 had this feature, albeit a little bit hidden, but all of a sudden CSS doesnt have even the slightest option to do this.
Its very disappointing to paying users, especially when you have millions paying upwards of a couple hundred per year to use your programs.

100% should stay true to pixel (300px should be on actual 300px)
but a feature only for print where I can choose to see the actual real-life size is a must

exactly like PS or Acrobat give us the option to enter our screen actual PPI and then add an option in "View"
let's call it "True-to-life" size.

Also since many of us now work on HIDPI displays, I would like to have an option to simulate my screen to HD so I will know the size of a banner, which the majority of viewers probably will see on HD monitors

I was the one that submitted this feature request.

100% view in Indesign is perfect on my monitor but Illustrator is way off. Does anyone else find that Indesign is fine?
I can hardly believe that this has so view votes too. I use Illustrator for print artwork all the time and use 155% for actual size. It seems so silly when you read 155% as actual size especially for software that is over 30 years old. I've used Illustrator since version 1 and have wanted this feature for a long time now.

I have suggested this--and ways to accomplish this--in multiple places. This is a huge advantage so you can view things at their intended size. The only way to do this is to place a ruler up on your screen and find what % zoom is Actual actual size. Then, you have to manually type this in or save as a view (which is limited).

Please add this feature!

THIS IS A MUST!

I wish they could sort this out, it is really sad that they can't fix such a simple thing. The measure a square with a ruler and enter the size solution is incorporated into embroidery software, so why not this much more sophisticated software?

oh god why this feauture has so few votes?

I think that could be easily resolved by allowing the user to set a custom dpi for Illustrator. The real size problem happens because Illustrator just assumes that your monitor is 72 ppi