How to snap windows on a Mac with a keyboard shortcut

To snap a window to half the screen on a Mac with the keyboard, press Fn ⌃ and the left or right arrow (on recent keyboards, Fn is the Globe key). That works on macOS 15 Sequoia and later, with no app to install. For thirds, two-thirds, or a shortcut that doesn't need Fn, you need a window manager. In Toolnotch's Wyndow, ⌃⌥← snaps the window to the left half, and pressing it again goes to two-thirds, then a third.

Below: what macOS does by itself, where it stops, and how Wyndow's keys work.

The built-in shortcuts (macOS Sequoia and later)

Apple added window tiling in macOS 15. The shortcuts live in the Window › Move & Resize menu of most apps:

You can also drag a window to a screen edge, or hold ⌥ while dragging to see where it will land. These options are in System Settings › Desktop & Dock › Windows, along with "Tiled windows have margins", which leaves a gap around tiled windows. Turn it off if you want windows edge to edge.

To use other keys, open System Settings › Keyboard › Keyboard Shortcuts › App Shortcuts, add a shortcut for "All Applications", and type the menu item's exact name, such as "Left". That's also how you give quarters a shortcut: macOS has the menu items but no keys for them.

On macOS 14 Sonoma and earlier, none of this exists. The green button's menu offers "Tile Window to Left of Screen", which puts the window in a separate full-screen Space, a different thing from tiling.

Where the built-in tiling stops

• Halves and quarters only. There are no thirds or two-thirds, which matter on a wide monitor or when a browser and a terminal don't need the same width.
• One key per position. Pressing Fn ⌃ ← again does nothing new. To get another size you need another shortcut.
• The other window doesn't move. Tile a window over one that already fills that half, and the first one disappears behind it.
• No real undo. Fn ⌃ R restores one window's size. It doesn't put back a pair you just arranged.
• Fn is awkward on external keyboards that don't have it.

Free apps cover most of this. Rectangle, which is open source, has thirds and lets pressing a key again cycle sizes. Magnet, a paid app on the App Store, does halves, thirds and quarters. If snapping is all you want, Rectangle is a good choice.

Snapping with Wyndow

Wyndow is the window manager in Toolnotch, an app that lives in the MacBook notch. Its keys all start with ⌃⌥ (Control and Option), so they don't need Fn and don't clash with macOS's own.

Every key can be changed or cleared in Settings, and the Shortcuts tab of the Wyndow panel (⌃⌥Space) lists them with your own keys.

Press again to change the size

⌃⌥← puts the window on the left half. Press it again and the window takes the left two-thirds, then the left third. With a second display, the next press sends the window to the display on that side, on the half that faces where it came from. With one display, it goes back to the half.

Wyndow reads the size from where the window is now, not from a timer. You can press ⌃⌥← once, work for ten minutes, press it again and get two-thirds. A window you resized by hand starts over at the half.

The other window makes room

If another window already fills the half you snap to, Wyndow moves it to the other half instead of covering it. Snap Safari to the left over a Terminal that was there, and Terminal goes right. Thirds work the same way: the window that was there takes a free third next to it. A quarter sends the one it covers to the quarter beside it.

It only pushes a window that fills the zone, is mostly visible and can be resized; one hidden behind others stays put. You can turn this off in Settings.

What you see

Each snap shows an island under the notch for four seconds: « Left half · Safari », or, when another window made room, « Left half · Safari ← · Terminal → ». The ⌃⌥⌫ keycap on the right reminds you of the undo, and a click on the island undoes too. A run of snaps updates the same island instead of stacking. Windows jump to their place, with no animation.

Undo

⌃⌥⌫ puts back the last window action: the snapped window and the one that made room, in one step. Press it again to go further back, up to the last 20 actions. If you moved a window by hand since, undo leaves that one alone; your later choice wins. The island says « Undone · 2 windows back ».

Snapping with the mouse: drag to the notch

If you prefer the trackpad, drag a window by its title bar up to the notch. As it gets close, a small face with a blue visor peeks out, and when you reach the notch a map of your displays opens: halves, thirds, quarters and maximize, drawn to scale, plus your saved desks. Move down onto a zone, a blue outline shows where the window will go on the real screen, and let go. Same island, same undo, and the other window makes room here too.

On a Mac without a notch, such as a Mac mini or an external display, the map opens from the middle of the menu bar.

Limits

• Full-screen apps. Wyndow never moves a window in macOS full screen.
• Two window managers fighting. If Rectangle, Magnet or another one is running, Toolnotch tells you. Keep the one whose keys you like and turn off the other's shortcuts, or turn off Wyndow and keep the rest of Toolnotch. When macOS's own edge tiling is on, Wyndow leaves the screen edges to it.
• Accessibility permission. Every Mac window manager needs it to move other apps' windows. Toolnotch asks the first time you press a window key.
• Not free. Toolnotch is a one-time purchase with no trial build; see pricing. The demo on the home page runs the real keys in your browser.

Wyndow also remembers your layout when you unplug a monitor: see why windows move when you unplug a display. To save a whole arrangement and call it back, see how to save and restore window layouts.

FAQ

What is the keyboard shortcut to split the screen on a Mac?

On macOS 15 Sequoia and later, Fn ⌃ ← puts the window on the left half and Fn ⌃ → on the right. Fn ⌃ ⇧ with an arrow puts the window and the one behind it side by side. On older versions there is no built-in shortcut.

Can I snap windows to thirds on a Mac without an app?

No. macOS tiles to halves and quarters only. Thirds and two-thirds need a window manager: Rectangle, Magnet, Moom or Toolnotch's Wyndow (⌃⌥D F G, or press ⌃⌥← three times).

Why does nothing happen when I press the shortcut?

The app moving windows needs Accessibility access in System Settings › Privacy & Security › Accessibility. If that's on, another app may own the same keys. With Wyndow, a key that can't move anything still answers on the island, with « No window to move » or « Window can't go there ».