How can I find the dimensions of an object?

Here's a quick solution that I always use:

Select the object as usual then hit Ctrl+T (Transform), there you can see the width/height showing up in the Info Panel.

And when you're done you can just click anywhere you like beside the selected object or hit Esc (Escape key) to cancel out the transform command.

Hope that helps, thanks!

Select the layer, then run this script:

var doc = activeDocument;
var lay = doc.activeLayer;
var width = lay.bounds[2]-lay.bounds[0];
var height = lay.bounds[3]-lay.bounds[1];
alert('Width = ' + width + ', Height = ' + height);

Choose the Layer that has the Object and place the layer in a new file so that it is the only layer. Trash the Layer's Lock (Fig 1)

Select the object, Inverse the Selection and Delete the area surrounding the object (Fig 2) [Note the topmost match].

Image > Trim... Transparent Pixels ... Top Bottom Left and Right (Fig 3)
Image > Image Size

You can change the. Pixels to another unit of measure

I realize this post is very old, but knowing that I came here without a solution and now having found one, I decided I'd share what I discovered after 15 minutes of desperation. Useful when you're trying to resize something based on its own dimensions or compare with other objects, where ruler and bounding boxes won't do.

It sort of depends on what you mean by "object." If the object is part of a flat image; say, a window in a photo of a building, then the measure tool is the way to go. With some additional work, you could make a selection of the object, then check the info panel for the selection dimensions. Same goes if the object is the lone contents of a layer. Load the layer as a selection and check the info panel.

The two methods that come to my mind, if your Object is smaller than your Image, would be to use the Measure Tool and the Info Palette, or to drag some Guides to act as "bounding boxes" and then drag the 0 point on the Rulers to the upper-most and left-most Guide. Probably several other methods too, so wait for the suggestions to come in - there're always several ways to do most things in PS.

Good luck,

Hunt

Image, Image size will tell you in PS