I'm probably late to the party, didn't get the memo, but I finally found out the UI can be resized. If someone's using a higher resolution and wants the UI to be easier to read they can upsize the UI, or if someone's on a smaller resolution and they don't want the UI taking up 1/4th of the screen they can downsize the UI.

It's in the C:\Users\<Name>\Documents\Electronic Arts\The Sims 4 folder, in options.ini file, as "uiscale". Found from this modthesims post: http://www.modthesims.info/showthread.php?t=544421

A google search only came up with one link, listed above. A lot of people might not know about this so thought I'd make a post. I'm just glad I just found out how to do it. Why wouldn't someone put a slider on the in-game options menu. It would be so much easier.

Well, that would be great... if I knew how to do it.
I can navigate to the folders, but then what do I do?

Thanks for the tip Bandon!

I discovered that if you change uiscale from 100 to 50, it becomes insanely huge. I'm going to go for 125 now. (I tried 150 but it was too tiny.)

Double click it, and it should open with Notepad, if not, then right click it and click "open with"
Then scroll down to UIScale = 100 and change the 100 to *whatever you want*, and hit save. backup your options before hand though.

Thank you, much.
Ha ha. Everyone should try 50, just for fun. Ack. It is huge.

I want to say thanks to you, as well, for posting this here. You have no idea how much you've improved my gaming experience.

Thank you!!

Yeah 50 makes it brand new game of how to actually find your sims behind the giant UI. ;D

Thank You so much I change mine to 75 and my game looks so much better now :D

Wow, that was easy for my bum brain. Thank you very much for the tip.

Awesome! Great find!

(I'm using Win 7)
Here's a screenshot. Double click on options. When it opens, scroll way down to uiscale. After you've made your change, in my case it's 75, close that window and it will ask if you want to save, click on okay.

Err, I think nitromon was asking for a screenshot of what the resized UI looked like in game play.................................

Ah. Could be. Well, here's a llama instead.

I'm curious - does resizing help with keeping the household thumbnails in one row (the eighth member always shows up above the first)? I suppose I could test myself, but I'm curious.

Ok I tried this and it's really cool. It helps with the loading screens and the icons in the game. I'm going to test size 85 since 75 was a tad too big. I wonder if the color of the UI can be adjusted using the same file. Anyway thanks for the help and it helps me a lot with my headaches and eye floaters.

I'm gonna have to show my sister this when I see her next. She plays this game and does something called "downsampling" so the UI is tiny. I will tell her to do this, whilst seeming really clever aswell

Also in that big picture, since it wasn't pointed out:

matchspeedstereomusic = 1

Set that to 0 and you won't get that stupid "fast forward the music!" effect.

Thank you! This has been in my mind for the past few days.
Edit: I was getting worried I couldn't find the UI scale option, but mine turned out to be at the very top.

my ui scale for ui is awesome now. But there is another big problem. Mouse cursor is not changed. It is too small for 4k. Is there a mod or some kind of option for make it bigger?

I didn't know this, but I do know that options.ini has quite a few tweaks that can't be adjusted ingame. One was frame rate max of 200fps, which is just plain overkill, since the human eye doesn't notice this much anyway, so I changed my max from 200 to 60fps and improve the performance, much less frame rate dropouts now when it tries to use 200fps when sometimes it can't.

I've found when changing the ui that my photos and paint from reference no longer work correctly...anyone know a workaround for this?

Hey! Did you find a solution? I Have the exact same Problem... :/