How to set up a two-thirds / one-third window layout on Mac
On any display bigger than a laptop, a 50/50 split is the wrong shape. Your main window — the editor, the document, the design — wants most of the width, and the thing you glance at — chat, docs, a terminal, a preview — only needs a strip beside it. That's the two-thirds / one-third window layout on Mac, and it's the split most people settle on once they try it. The catch: macOS can't make it for you. Here's why, the manual workaround, and how to get it from the keyboard in a couple of seconds.
Why two-thirds / one-third beats a 50/50 split
A half of a 27-inch display is wider than most text needs, and a half of a laptop screen is narrower than most apps like. Two-thirds fixes the first problem: on a 27-inch or 32-inch screen, two-thirds is roughly the width of a comfortable laptop display, which is what most apps are designed around. And one-third is still wide enough for the things that only need to be visible — a Slack channel, a reference page, a log tail, a video call, a live preview.
It also matches how work actually splits. You rarely have two equally important windows. You have one thing you're making and one thing you're consulting, and giving them equal space is giving the consulting window too much.
When it's not the right layout: on a 13- or 14-inch MacBook a third is too narrow for most apps, so stick to halves (see window management on a small MacBook screen). On a 21:9 or 32:9 ultrawide you'll usually want more columns than three — our ultrawide guide covers that.
Can macOS do two-thirds natively?
No. macOS has two built-in window features and neither has a two-thirds preset.
Window tiling (hover the green button, use Window → Move & Resize, or the 🌐 Control + arrow shortcuts) offers halves, quarters, Fill and Center, plus arrangements like Left & Right and Left & Quarters. Every one of them is built from halves and quarters. There is no thirds option and no shortcut for one — and macOS 27 kept the same ceiling.
Split View (the full-screen two-window mode) starts at 50/50, but it does let you drag the divider between the two apps. That's the only built-in way to get an uneven split — with the costs that come with Split View: both apps go full screen in their own Space, there's room for exactly two windows, and some apps refuse to shrink past a minimum width.
The manual workaround
If you want it without installing anything:
- Tile your main window to the left half with 🌐 Control ←.
- Drag its right edge out until it covers about two-thirds of the screen.
- Tile or drag the second window to the right, then drag its left edge until it meets the first. macOS windows snap lightly to each other's edges, which makes the line-up easier.
It works. But it's mouse work, it's approximate, and you redo it every time a window gets moved, reopened, or bumped to another display.
Your options for a two-thirds / one-third split
| Method | 2/3 + 1/3? | Keyboard-only? | Cost |
|---|---|---|---|
| Native window tiling | No — halves and quarters only | Yes, for halves | Free (built in) |
| Split View + dragged divider | Approximately, full screen only | No | Free (built in) |
| Rectangle | Yes — dedicated two-thirds commands | Yes | Free (open source) |
| Magnet | Yes — left/right two-thirds | Yes | Paid (App Store) |
| Let's Tile | Yes — on its free 3 × 2 grid | Yes | Free; Pro $9.99 one-time |
Rectangle is the free, open-source answer: alongside left, center and right thirds it has First Two Thirds and Last Two Thirds commands, each bindable to any shortcut you like. Magnet on the App Store also covers left and right two-thirds alongside its thirds. Both are reliable, and if you already have one installed, check its shortcut list — you probably already own this layout.
The cost with both is the shortcut-per-layout model. A 2/3 + 1/3 setup needs two chords (the two-thirds one and the matching third), the mirror image needs two more, and they're easy to mix up until they become muscle memory.
Two-thirds / one-third in Let's Tile, step by step
Let's Tile works differently: one shortcut opens a visible grid over your window, and you steer a highlighted "ghost" into the cells you want. The free grid is 3 columns × 2 rows, so thirds and two-thirds are exactly what it's shaped for — and it's free with no time limit. It's also the layout the demo on the Let's Tile page shows.
The one-third window (say, chat on the left):
- Focus it and press ⌘ ↵ — the grid appears with the ghost in the top-left cell.
- Press ⇧ ↓ to stretch the ghost down to the full left column.
- Press ↵. The window snaps to the left third.
The two-thirds window (your main work):
- Focus it and press ⌘ ↵.
- Press → to move the ghost to the middle column.
- Press ⇧ → to stretch it across the right two columns, then ⇧ ↓ for full height.
- Press ↵. It fills the right two-thirds.
Want the main window on the left instead? Same keys, mirrored: ⇧ → then ⇧ ↓ from the top-left gives you the left two-thirds; → →, ⇧ ↓ puts the other window in the right third. Because the grid is on screen while you do it, there's nothing to remember — you're pointing at cells you can see.
If you outgrow 3 × 2, Let's Tile Pro is a one-time $9.99 — no subscription, no account, one key for up to 20 devices — and adds any grid you like (reshape it live with ⌥ + arrows: a 4-column grid gives you a three-quarters / one-quarter split on wide screens), a different grid per display, throwing a window to your other display mid-tile, and margins between cells. In fairness: Let's Tile is newer than Rectangle and Magnet, and it isn't open source — if either matters to you, Rectangle is the honest pick.
Making the layout stick
- Decide which side is "main". Put the two-thirds window on the side you face. On a single display that's usually the left, where your eyes start a line; on a two-monitor desk, put it on the side nearest your other screen.
- Use the third for things you watch, not things you edit. If you find yourself typing in the third all day, swap them.
- Get between them without the mouse. Two tiled windows are only half the workflow; jumping between them is the other half. Cmd-Tab switches apps, so two windows of the same app are a problem — Let's Switch goes straight to the window instead.
- Accept that layouts get disturbed. Displays sleep, apps reopen at old sizes. A layout you can rebuild in two keystrokes beats one you have to rebuild by dragging. Our guide to saving window layouts on Mac covers the tools that remember a whole arrangement.
Frequently asked questions
Can I split my Mac screen two-thirds and one-third without an app? Only roughly. Native window tiling has no thirds, so you either drag the divider in Split View (full screen, two apps only) or tile to halves and drag the edges by hand.
Is there a keyboard shortcut for two-thirds on Mac? Not built in. Rectangle, Magnet and Let's Tile all add one — Rectangle and Magnet as dedicated two-thirds commands, Let's Tile as a grid you steer with the arrow keys.
What about three equal columns? Same grid, different cells — see how to put three windows side by side on Mac.
What's the best screen size for a two-thirds / one-third layout? It earns its place from about 24 inches up. Below that, halves are usually better; on an ultrawide, consider four or more columns.
More on keyboard window management on the Let's Suite blog.