What resolution does a ChatGPT image need for an 8.5 x 11 flyer?

About 1,403 × 1,815 pixels prints sharp on letter paper. ChatGPT's usual 1024 × 1536 image gives about 120 PPI there, which prints but looks soft; a square 1024 × 1024 image gives about 93 PPI and looks blurry.

Do I need 300 DPI to print?

Only for small things held in the hand, like business cards. Posters are read from further away and need far fewer pixels per inch.

PrintSanity

What size should an AI image be for printing?

Ask an image model for the pixels in the first column and it will print sharp at that size. Below the second column it prints visibly blurry.

Each image fitted to the page without cropping. Sharp, soft and blurry are judged at the distance each size is normally read from: soft prints, but small text and thin lines go fuzzy.
Print	Ask for (px)	Never below (px)	ChatGPT tall 1024 × 1536	ChatGPT square 1024 × 1024
Business card 3.5 × 2 in	1,019 × 582	679 × 388	SHARP	SHARP
4 × 5 in	1,164 × 1,455	776 × 970	SOFT	SOFT
Postcard 4 × 6 in	1,164 × 1,746	776 × 1,164	SOFT	BLURRY
A6 4.1 × 5.8 in	1,203 × 1,696	802 × 1,131	SOFT	BLURRY
Invite 5 × 7 in	1,330 × 1,862	890 × 1,246	SOFT	BLURRY
5 × 8 in	1,215 × 1,944	810 × 1,296	SOFT	BLURRY
A5 5.8 × 8.3 in	1,323 × 1,877	880 × 1,249	SOFT	BLURRY
8 × 10 in	1,432 × 1,790	952 × 1,190	SOFT	BLURRY
Letter 8.5 × 11 in	1,403 × 1,815	935 × 1,210	SOFT	BLURRY
A4 8.3 × 11.7 in	1,323 × 1,871	885 × 1,252	SOFT	BLURRY
Legal 8.5 × 14 in	1,190 × 1,960	791 × 1,302	SOFT	BLURRY
11 × 14 in	1,419 × 1,806	946 × 1,204	SOFT	BLURRY
Tabloid 11 × 17 in	1,243 × 1,921	825 × 1,275	SOFT	BLURRY
A3 11.7 × 16.5 in	1,322 × 1,869	877 × 1,241	SOFT	BLURRY
12 × 18 in	1,272 × 1,908	852 × 1,278	SOFT	BLURRY
16 × 20 in	1,424 × 1,780	960 × 1,200	SOFT	BLURRY
Poster 18 × 24 in	1,368 × 1,824	918 × 1,224	SOFT	BLURRY
Large poster 24 × 36 in	1,272 × 1,908	840 × 1,260	SOFT	BLURRY

Why not 300 DPI for everything?

300 is the right number for something held in your hand, like a business card or an invitation. A poster is read from across a room, where the eye can't see detail that fine, so it needs far fewer pixels per inch. A 24 × 36 poster is sharp at around 53 PPI from where people stand to read it.

That's why ChatGPT's tall image is sharp as a business card and soft at every size above it, while its square image, fitted to a tall page, is blurry from a postcard up.

The shape matters too

ChatGPT's portrait images are 2:3. Letter paper is closer to 3:4. Print one on the other and either the edges are cut off or there are white bars. Ask for the exact pixels above, or let PrintSanity fit it to the paper without cropping.

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