1. Height And Width Pixels
2. Pixel Width In Inches
3. Width By Height Or Height By Width
4. Measure Pixel Width
5. Width Height Pixel Mac App For Windows 10

The pixel dimensions. The width and height of an image, in pixels, are known as its pixel dimensions, and in Photoshop CC, we can view them next to the word Dimensions near the top of the dialog box. Here we see that my image has a width of 4509 pixels (px) and a height of 3000 pixels. This app allows you to resize an image to whatever size you like (with limitation), quickly and easily. It is a really resizer app. You can specify the output format using one of the following four units of measurement: pixels, millimeters, centimeters, inches To preserve aspect ratio just tap on the chain icon between width and height input fields. Image Size gives you the option of saving. So the width adjusts when you change the height and vice versa. 8×10 inches at 300 ppi, this is the size needed for printing an 8×10. Notice the pixel size is 3000 x 2400.

Image pixel density for web and app design is often seen as a confusing topic. I’m not sure why this is — when stripped back to the bare essentials, the reality is far less complex than you might think.

Bitmap images are two dimensional grids of pixels, with a width and a height. They often also contain meta data, which may include pixel density. Pixel density is often described as pixels pixels per inch (PPI) or dots per inch (DPI).

The two names, PPI and DPI, mean essentially the same thing — the number of pixels contained within a vertical or horizontal inch. 300PPI means that there’s 300 pixels contained within each one inch row. A one inch by one inch square in a 300PPI image contains 90,000 pixels, because it is a 300 × 300 pixel square. Most displays have a fixed resolution grid, so their pixel density can’t change. A Retina iPad Air display is 264PPI, because there’s 264 elements per inch in the display that can each only ever represent one pixel.

The pixel density stored in image files is different. It’s just meta data that’s saved alongside the image data. It can be changed at any time without affecting the image data at all. It should be considered a relic from the printing industry, because in general, web and app development display all images so that one pixel in the image equals one on screen, ignoring the embedded pixel density information.

Pixels per inch (PPI) vs dots per inch (DPI) vs lines per inch (LPI) #

Purists will probably use PPI to describe on screen pixel density and DPI to describe print density, but I think this is a battle that’s drawing to a close. Apple, Microsoft and Google all seem to prefer using DPI in their literature. Curiously, Apple’s iPhone 4S and iPad specs describe their displays using PPI.

For screen design, PPI and DPI are interchangeable.

For print design, DPI only exists to indicate the final size the image might be printed. It’s sometimes used to generate thumbnail images to help performance in layout apps. It can also be used to indicate optimal print size — InDesign, Xpress and others treat 100% image size as meaning “the physical size you’ve used the image in your layout matches the pixel density tag contained in the image”. That’s a great feature. If the images are set up correctly, you know how large you can make images without risking pixelation. It’s still just a tag associated with the image. A handy tag, but a tag nonetheless.

Lines per inch (LPI) is a printing-specific term that describes how close together the halftone lines are. Not all printing is 300DPI — coarser line screens, like those used for newspaper and large format printing (billboards etc), mean lower pixel density images can be used.

The history of 72PPI #

The original Mac, the Macintosh 128K, featured a 512 × 342 pixel, 72PPI black and white display. Because of this, macOS has considered 72PPI to be baseline where one image pixel equals one display pixel, even though most Mac displays are far higher density than 72PPI.

macOS’s Preview can view one image pixel as one display pixel, or it can scale using the PPI tag within the file.

It’s just metadata #

If you’d like to set up your Retina iPad Photoshop documents at 264PPI, be my guest. You could also set them up at 72PPI. It really doesn’t matter, as long as the final result is images with the correct pixel dimensions.

However, if you plan to use Photoshop and different pixel densities for each document, dragging layers and copying layer styles between documents scales layer styles — dragging a layer from a 326PPI Retina iPhone document to a 264PPI Retina iPad document will mean all layer styles get scaled by 20% (then rounded to the nearest integer). And that’s probably not what you want. Also, macOS’s Preview will display 72PPI images at the exact size, no matter how you have it set up.

It is for these reasons I assign 72PPI to all my design documents, and I recommend you do the same. To change the pixel density of your Photoshop document without resizing the image data, open the Image Size dialogue, uncheck Resize Image and type in the desired pixel density.

Published 16 March 2012.

Why didn't I think of that?

A much better option than Free Ruler is PixelStick. It isn't in the way as much as Free Ruler, and it lets you measure angles and distances along an angle too.

Yeah, I've been doing this for a while now. It's so fast and easy for web design. I also didn't think it was a hint, but it can save tons of time. I'm glad others will know about this now.

A+

ditto for using it for years and not thinking it was hint-worthy.
Note: the hint requires at least Leopard. The coordinates aren't shown in Tiger.

Bonus tip: hold down the spacebar after you start dragging, and you can move your entire selection around without starting over. Makes it easy to get the positioning exactly right.
I formed this habit in Illustrator, and at some point I must have tried it as an automatic reflex when taking a screenshot. Was surprised and delighted that it worked. I believe this feature was added in Snow Leopard.

Hey that's really cool. That seems tip-worthy to me in and of itself.
Rob

I agree. It's a great tip, and some great tips here in the comments.
I love the part about holding down the spacebar after you start dragging.
I just tried PixelStick and I'm grateful to have learned of it here, in these comments.
Thanks!

Height And Width Pixels

PixelStick is my favorite measuring tool, but, honestly, i never thought to use the screen capture..
I think that's a really good tip, thank you!

I love the spacebar trick - very neat! And also really pleased to have found out about PixelStick - I won't use it for everything but I think I'll certainly use it enough that I've already given it a space on my Dock!

I never thought of using modifier keys for screen capture, but hey, it actually works:
shift: horizontal or vertical selection only, depending on the movement you were making
option: use a centered starting point
option-shift: like shift with centered starting point
space: move it around
so cooool ... thanks .....

Pixel Width In Inches

cool !
I use the screen zoom feature for handicapped people and have set it so holding down 'ctrl-alt-cmd' and using the scroll-wheel zooms the screen. Maybe good to zoom in first to measure more precisely.
I use screenshots a lot and was blown away by the modifier keys working !!

Width By Height Or Height By Width

Hi guys,
I've recently created a small app that is just amazing when it comes to measuring items on screen. It's workflow is a lot better than a standard ruler. Check it out at http://pixf.it
It automatically finds the edges of the item you want to measure offering you a choice of copying the dimensions to the clipboard in a couple of different formats. Hope you enjoy it.
Cheers!

Measure Pixel Width

Along with a few tools that you have to buy, you can still measure pixels on the Mac with its stock application. There is a Grab utility, you can capture screen selection, it will create window with an image of selected area (not saved to the disc yet), then you can go to Edit -> Inspector and it will show dimensions of selected area (it will also show dimensions as a tooltip during selection process). Good thing is that captured image isn't saved to the disc, you can just dismiss it. Not great, but does the job. It also supports delayed capture which is good for capturing popup menus and such.

Width Height Pixel Mac App For Windows 10

I second the recommendation of PixelStick. Its an awesome, light and handy little app for anyone measuring (in any app or in maps) and working with colors.
http://plumamazing.com/mac/pixelstick