Excuse me, maybe someone asked before?

When I'm drawing a box in AI likes 200x200mm, but the dimension shown 200.xxx .Always a DECIMALS,

enter image description here

When I'm open a new file in PS likes 255x255mm, but the image size shown 255.02 .Always a DECIMALS too.

enter image description here

Every single size likes this problem, can I fix it or this is a bug of Adobe?

thanks a lot!

| improve this question | | | | |


For illustrator there is are 2 possible (common) reasons for apparent size issues:

  • The square is 200 mm across but since your stroke is symmetrically on both sides of this line the bounding box is thus bigger (You can change settings not to account for stroke though). This is most likely answer as a postscript point is exactly 0.353 mm.

  • Snap to pixel grid is enabled in Illustrator, this would be the default for any rgb document. Thus illustrator would round to nearest 1/72:th of an inch.

In addition its good to know that the canonical unit in illustrator is a point so even exact looking numbers in Illustrator are still rounded by computer arithmetic, if your really pedantic about things. By the way this applies to all but symbolic computations.


As for Photoshop 300 dots per inch resolution means that a image can only be a number that is a multiple of 1/300:th of an inch since you can not have fractional pixels. This means that a rounding has to happen. You can change resolution to pixels per cm and now you dont get fractional mm if you choose the resolution wisely.

Working as intended

Everything is indeed working as intended.

| improve this answer | | | | |

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.