How to use mouse buttons in Photoshop on a Mac
InputConfig is completely free on the Mac App Store. You don't have to make an account, there are no subscriptions, and nothing is locked. Optimized for Apple silicon.
On a Mac, the way to put a Photoshop job on a mouse button is to make the button press the shortcut key Photoshop already has, such as the left bracket for a smaller brush or Command Z for undo. Photoshop's own Keyboard Shortcuts dialog is built for keys, and the Adobe community threads about side buttons that I read on October 21, 2026 mostly end at the mouse maker's software. InputConfig, the free Mac app I make, does the key part for any mouse, and it can switch to a Photoshop layout only while Photoshop is in front. This app is completely free, and you do not have to make an account.
Every Photoshop key on this page comes from Adobe's list of default Photoshop shortcuts, which I read on October 21, 2026. If you would rather use a MIDI pad or a tablet's buttons, see a MIDI controller for Photoshop and the drawing and photo editing guide. This page is about the mouse.
On this page: 10 sections
What Photoshop and macOS give a mouse
Photoshop reads the left button, the right button and the wheel by itself, and everything past that is yours to add. The Mac's own mouse settings, in System Settings, Mouse, change speed, scrolling and secondary click, and they do not hold Photoshop shortcuts. The mouse maker's software can send keys per app on a Mac, for example Logi Options+ for Logitech or Razer Synapse for Mac, and that works if you own that brand.
The mapper route is different in one way: it works for any mouse that shows up as a mouse, and the layout lives in one place. The picture is the same everywhere. A side button becomes a keystroke, and Photoshop only ever hears the keystroke.
One Adobe community thread I read on October 21, 2026 reports a Logitech MX Master's back and forward buttons scrolling sideways in Photoshop after an update. I did not reproduce that, and I do not know the cause. If a button does something odd in Photoshop, Scan it first and decide what it should do from there.
Find out what each button sends
A mouse button reaches the Mac as Left click, Right click, Middle click or Button 4 and up. InputConfig reads all of them from the device This Mac's mouse or trackpad, and one mouse counts as one device. Press Scan, then click the button. If Scan names a key instead of a mouse button, the mouse is sending a key, and the fix is on F13 to F19 on a Mac.
| Button | How it usually reports | A good Photoshop job |
|---|---|---|
| Left click and right click | Left click and Right click | Leave them alone. They cannot be blocked, so a shortcut there fires on every normal click. |
| Wheel press | Middle click | Hand tool while held, or Fit in view. |
| Side buttons | Button 4 and Button 5 | Smaller and bigger brush. |
| Thumb grid or extra buttons | Button 6 and higher, found under More buttons up to Button 32 | Undo, step backward, eraser, swap colors. |
| Tilt wheel | Sideways scroll | Brush hardness, with one row per direction. |
| DPI or profile button | Usually nothing the Mac can read | Nothing. If Scan hears no press, no app can read it. |
The mouse tester on this site shows every button a mouse sends before you open the app. Ten minutes with Scan saves an evening of wondering which button is which.
Put the Photoshop keys on the buttons
Start with the pair most people want first, brush size. Photoshop lists the left bracket as decrease brush size and the right bracket as increase brush size, and Shift with the brackets (the curly brace keys in Adobe's table) changes hardness.
Step 1: Scan the side button
- You: Add a row, set the device to This Mac's mouse or trackpad, the input to Mouse and the kind to Button, then press Scan and click the side button.
- InputConfig: Names it, for example Button 4.
- Check: The row shows the button's name.
Step 2: Give it the key
- You: Set the output to Keyboard Key and pick the left bracket. Add a second row for the other side button with the right bracket.
- InputConfig: Presses that key each time you press the button.
- Check: In Photoshop, with the Brush tool active, press the button and the brush circle shrinks. Press the other and it grows.
Step 3: Stop the old job
- You: Open the row's Options and tick Block the button's own action in the Press box.
- InputConfig: While the preset runs, apps stop seeing that button.
- Check: Press the button once. Brush size changes and nothing else happens.
Here is the table I would start from, using the keys in Adobe's default list on a Mac.
| Job | Photoshop key | Good home |
|---|---|---|
| Smaller or bigger brush | Left bracket and right bracket | Button 4 and Button 5 |
| Softer or harder brush | Shift left bracket and Shift right bracket | Tilt left and right, or Button 6 and 7 |
| Undo last command | Command Z | A thumb button |
| Step backward and forward in history | Command Option Z and Command Shift Z | Two neighboring thumb buttons |
| Zoom in and out | Command plus and Command minus | Two thumb buttons |
| Fit in view and 100 percent | Command 0 and Command 1 | Wheel press and a thumb button |
| Hand tool | Space, held | A thumb button |
| Zoom tool, in and out | Command Space and Option Space, held | A pair of upper buttons |
| Brush and eraser | B and E | Two thumb buttons |
| Default colors and swap | D and X | Two thumb buttons |
Macros and multi-step jobs
A row can run a short macro instead of one key. In the row's Options, tick Run a sequence of steps (macro), then add steps. Each step is a key, a shortcut or a click, with its own wait and hold time.
- Reset and flip colors. A tap of D sets Photoshop's default colors, and a tap of X swaps them. Two steps on one button give you the opposite pair of colors, which is the quick way to switch between painting and erasing on a mask.
- Brush at the ready. A tap of B followed by a tap of D picks the Brush and the default colors together.
- Fit, then 100 percent. Command 0 and, after a short wait, Command 1. It is handy for checking an edge at full size and returning.
I have not run these exact macros in Photoshop myself. They use shortcuts from Adobe's list, so if one does nothing, check that Photoshop is the front app and that a text layer is not being edited. Keep a macro short, because every extra step is one more place for Photoshop to be busy.
Hold, repeat, tap twice and switch by app
These options turn four buttons into more than four jobs, and all of them sit in a row's Options.
- Repeat keys while held. On the brush size rows, this makes a held side button keep shrinking or growing the brush, like holding the bracket key on the keyboard. Leave it off for undo.
- Fires while held. This is the default. The key stays down as long as you hold the button, so a Space row makes a thumb button a hand tool you hold, and you drag with the left button while it is down. Photoshop only switches to the Hand tool this way when you are not editing text.
- A tap and a hold on one button. A quick tap sends the normal output, and holding past a time you set sends something else. A good split is undo on the tap and step backward on the hold.
- Block the button's own action. Available for the middle button and the side buttons, so an app stops seeing them while the preset runs.
Now keep the layout out of other apps. In the preset, open Automation & Gaming Utilities, add Photoshop under Activate when these apps are in front, and in Settings, Advanced, turn on Switch presets when the front app changes. Only one preset runs at a time, so each app gets its own preset, and the one for Photoshop starts when Photoshop comes forward. The longer guide is different mouse button actions per app.
The emergency stop is Control Option Command period. Brackets on side buttons in Photoshop would type brackets in a text app, so let the layout follow the app.
Layouts for the mouse you actually have
- A mouse with a thumb grid. Photoshop is a good place for one. Put the tools on the first row, B, E, V and L, and undo and step backward on the second. The MMO mouse page covers the grid itself.
- A trackball. Hold the big button for Space and the hand tool, and keep brush size on the two small buttons, so the ball only ever positions the cursor.
- A vertical or ergonomic mouse. It usually has just two side buttons. Brush size on those two, and undo on a hold of the wheel press, keeps the hand in one place.
- A pen user with a mouse in the other hand. The pen does the painting, so the mouse is for the quiet jobs: undo, zoom, hand. See drawing tablet buttons for the pen side.
I would begin with brush size and undo, and add one job a week. A layout you can remember without looking beats a full one you cannot.
If a button does nothing in Photoshop
Climb this ladder, smallest step first:
- Check the preset is on. Rows do nothing until you click Activate, and the preset must be the one that runs for Photoshop.
- Check Accessibility. In System Settings, Privacy & Security, Accessibility, InputConfig must be allowed.
- Check the Scan. If the button never scans, it only talks to the maker's software. If it scans as a key, set it to F13 to F20 there first.
- Check the tool. Brackets size the active painting tool, so choose the Brush first. Space needs the document, not a text layer, in front.
- Quit the maker's software. Logi Options+ and similar apps can take a button over. Quit it, or set the button to a plain click there.
- Try it in another app. Press the same button in TextEdit. If the key appears there, the row works and the trouble is inside Photoshop.
What it cannot do
- Tell two mice apart. Every mouse connected counts as one device, so one button cannot do two jobs for two mice.
- Change brush feel. Pressure, smoothing and brush settings are Photoshop's. InputConfig only sends keys, clicks and scrolls.
- Change speed or DPI. The maker's app, or LinearMouse, Mac Mouse Fix or SteerMouse, does that, and they run alongside InputConfig.
- Read private buttons. A DPI or profile button that never reaches the Mac cannot carry a Photoshop key.
- Replace a drawing tablet. A mouse has no pressure, so it adds shortcuts and does not replace the pen.
The short version
- Keys, not buttons. Photoshop takes keys, so each mouse button sends one. Brackets for size, Command Z for undo, Space for the hand.
- Scan and block. Scan the button, then block its old action on side and middle buttons.
- Follow the app. Give the preset Photoshop under Activate when these apps are in front.
Start with the two side buttons on the brush brackets, and you will feel the difference in the first minute.
Questions
Can I change brush size with a mouse button in Photoshop on a Mac?
Yes, with a mapper. Put the left bracket and the right bracket, which are Photoshop's brush size keys, on two side buttons in InputConfig, and tick Repeat keys while held to keep changing the size.
Can I assign a mouse button to undo in Photoshop?
Photoshop only takes keys in its shortcut dialog, so assign Command Z to the button in InputConfig. A hold action can send Command Option Z, which steps backward, on the same button.
How do I use the hand tool on a mouse button in Photoshop?
Set a thumb button to the Space key. It stays down while you hold the button, so you can drag with the left button to pan, as long as you are not editing text.
Why do my mouse side buttons scroll sideways in Photoshop?
One Adobe community thread reports this with a Logitech mouse after an update. Scan the button, bind your own key, and tick Block the button's own action, and check the maker's software if it still happens.
Does this work with a Magic Mouse in Photoshop?
A Magic Mouse has no side buttons, so it offers fewer places for keys. See the Magic Mouse page for what it does report.
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