The Magnet app for Mac, and an alternative that lets you build your own layout

The Magnet app snaps Mac windows to halves, thirds and quarters, plus any custom sizes you set up as commands. Screen Divider lets you design the grid yourself — and merge any block of cells into a single zone — then drag windows into it.

What Magnet does well

Magnet, from Bootcode, has been on the Mac App Store since 2012 and costs $4.99 there with a perpetual license, no subscription and no in-app purchases. You can snap a window by dragging it into trigger areas at the screen edges and corners, with keyboard shortcuts, or from the green-button menu, and you can add as many custom commands as you like for sizes the built-in halves, thirds and quarters don't cover. It handles external and vertical displays and can sync its settings over iCloud. For quick, reliable snapping at a low price, it is a solid choice.

How Magnet works

Magnet’s own site (checked October 21, 2026) describes three ways to trigger it: dragging, customizable keyboard shortcuts, or the menu bar. When you drag, the screen edge you hit decides the size:

• Corners snap a window into a quarter of the screen.
• Left and right edges give you halves.
• The top edge maximizes the window on that screen.
• The bottom edge makes thirds, and sliding along it expands the window to two-thirds.

On a vertical display it adapts: thirds run along the sides, while quarters and halves move to the corners and the bottom edge. Magnet supports up to six external displays. Its FAQ adds two limits worth knowing: it needs macOS 13 Ventura or later, and it arranges windows within the active Space but not across different Spaces. Neither its site nor its Mac App Store listing mentions a free trial, so the $4.99 is paid up front.

Where Screen Divider is different

Screen Divider is built around a layout you draw rather than a list of commands. You open a visual editor, split the screen into halves or thirds as finely as you like, and then merge any adjacent cells into one zone: a top three-quarters, a wide center, a tall sidebar. When you drag a window, an overlay shows the zone it will land in, and releasing snaps and resizes it to fit.

So the difference is in how you set it up. In Magnet each spot is its own command. In Screen Divider you draw the whole arrangement once, for example "top three-quarters plus a short bottom bar", and every zone in it is a drop target. Each display keeps its own layout.

Checked on October 23, 2026: Magnet is $4.99 on the US Mac App Store, version 3.0.7 (last updated April 2025), macOS 13 or later.

Which should you choose?

If you want keyboard shortcuts, a low price and an App Store install, Magnet is great and we won't pretend otherwise. If you'd rather draw your layout once, with merged rectangles and uneven zones, and snap into it by dragging, Screen Divider is built for exactly that. Want more power than either? Our Moom alternative comparison covers the most feature-packed option, and the Divvy comparison covers the classic grid tool. Weighing Magnet against free Rectangle? Here’s our side-by-side Rectangle vs Magnet comparison.

On a tight budget? Our BetterSnapTool alternative page compares the $1.99 drag-to-edge snapper fairly.

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