How to crop a picture on your Mac

Your Mac has two free croppers. Preview crops to any box you drag and shows its size in pixels. Photos crops to set ratios like Square, 4:5 and 16:9, or a custom one, but only for pictures in your library. Neither offers 9:16 in one click, and neither lets you type an exact width and height and see the box.

Koi's Shift wheel has a Crop tool that does both: ratios from 1:1 to 9:16 and a Width and Height you type. We make Koi, so read that part with that in mind. Apple's steps come from its own guides, checked October 21, 2026.

From Apple's Preview guide:

1. Open the picture in Preview.
2. Click Show Markup Toolbar if it's hidden, then click Rectangular Selection.
3. Drag across the part you want to keep.
4. To see the box's size, choose Tools, Show Inspector, click the Crop Inspector and pick pixels as the unit.
5. Click Crop in the Markup toolbar, then choose File, Save.

Changed your mind? Edit, Undo Crop works right away. Later, File, Revert To, Browse All Versions brings back an earlier version. Preview crops the file itself, so duplicate it first if you want to keep the uncropped picture.

For pictures in your library, Apple's Photos guide has ratios built in:

1. Double-click the photo, then click Edit.
2. Click Crop in the toolbar.
3. In the sidebar, click a ratio: Square, 4:5, 16:9 and others. Choose Custom to type your own, like 9:16.
4. Drag the rectangle round what you want to keep.
5. Click Done.

Apple warns that a crop changes the photo everywhere it appears in Photos, in albums and slideshows too, so duplicate it first if you need both. Photos sets a ratio, not a size in pixels: export the cropped photo, then resize it if a site wants an exact size.

1. Start dragging the picture, from Finder, the desktop or another app.
2. While you're still holding it, press and hold Shift. A wheel opens round your pointer.
3. Drop it on Crop. The picture opens with a crop box over it and the rest darkened.
4. Under Aspect ratio, pick Free, 1:1, 16:9, 9:16, 4:3 or 3:4. The box keeps that shape as you drag it.
5. Or type the box's Width and Height in pixels under Size. Original shows the picture's own size, so you know the limit.
6. Drag the box by a corner, an edge or its middle until it frames what you want.
7. Click Save cropped copy. “Photo cropped.jpg” lands beside the original.

• Reset puts the box back round the whole picture.
• JPEG, PNG, HEIC and TIFF stay what they were. A WebP or RAW, which your Mac can read but not write, is saved as PNG.
• The original is never touched, and nothing is uploaded.

A site asks for 1080 by 1080. Two different things can get you there, and mixing them up is why crops come out wrong.

• Cropping cuts. Typing 1080 by 1080 in Koi's Crop keeps a 1080 pixel square of the photo, at full detail. On a 4000 pixel photo that's a small part of it.
• Resizing scales. Preview's Tools, Adjust Size makes the whole picture smaller, keeping everything in it.

For the whole photo at exactly 1080 by 1080:

1. Crop it to 1:1 first, with Koi's Crop or Square in Photos.
2. Open the square in Preview and choose Tools, Adjust Size.
3. With Scale proportionally on and pixels as the unit, type 1080 as the Width. The Height follows.
4. Click OK and save.

Koi's Crop doesn't scale a picture. Its Compress can make one smaller, down to set sizes from 3840 to 800 pixels on the long side, but not to any number you type: see how to compress an image on Mac.

The quickest crop is the one you never have to do. Press Shift-Command-4 and drag across only the part you want, and the screenshot is already cropped, as Apple's screenshot guide shows. Press Esc to cancel. For one window, press Space after Shift-Command-4 and click it.

For a video, Koi's video wheel has its own Crop: the same box and ratios, over the video's first frame, saved as a cropped copy of the whole video.

• The picture looks blurry after cropping. You kept a small part of it, so it has few pixels. Crop less, or start from a bigger original.
• The crop saved over your original in Preview. Duplicate first, or use Browse All Versions to get it back.
• A screenshot crops at twice the size you expect. A Retina screen's screenshots have two pixels for every point, so check the size in pixels, not by eye.
• A site still says the size is wrong. It wants an exact size, not a ratio. Resize after cropping, as above.

• A quick freehand crop of any file: Preview.
• A photo in your library to Square or 16:9: Photos.
• Any picture to 1:1, 16:9, 9:16 or a typed size, without opening an app: Koi's Crop. The same wheel makes collages and annotates screenshots. Cutting a video instead? Koi's video wheel has its own Crop: see the Shift wheel.

Crop comes with Koi on every plan. Pro is $20 a month, or $192 a year, after a 3-day free trial that needs a card. Lifetime is paid once, from $59. See the plans, or how to use the Shift wheel.