How to Resize Brush with Shortcuts in GIMP

Resizing your brush directly on the canvas streamlines your painting and editing workflow in GIMP. Instead of manually adjusting sliders in the Tool Options panel, you can use built-in keyboard shortcuts, modifier keys combined with your mouse wheel, or custom input controllers to dynamically change brush radius on the fly.

Default Keyboard Shortcuts for Brush Size

GIMP includes built-in keyboard shortcuts that change the brush radius incrementally while hovering over the canvas:

  • Decrease Brush Size: Press the left bracket key [
  • Increase Brush Size: Press the right bracket key ]

Holding either key down will continuously shrink or expand the brush radius until you release it.

Interactive Resizing with the Mouse Wheel

For faster and smoother control directly over your subject, use the mouse wheel combined with keyboard modifiers:

  1. Hover your cursor over the canvas where your brush is active.
  2. Hold down Ctrl + Shift.
  3. Scroll the Mouse Wheel Up to increase the brush radius.
  4. Scroll the Mouse Wheel Down to decrease the brush radius.

This combination allows you to visually gauge the brush footprint against your artwork in real time.

Customizing Brush Size Shortcuts

If the default combinations do not fit your workflow, you can rebind them to any preferred keys:

  1. Open the top menu and navigate to Edit > Keyboard Shortcuts.
  2. In the search bar at the top, type Brush Size.
  3. Locate the actions named Increase Brush Size and Decrease Brush Size (or Increase Brush Size More for larger increments).
  4. Click on the shortcut field next to the action and press the desired key or key combination.
  5. Click Save to apply the changes.

Enabling Mouse Wheel Resizing Without Modifiers

You can configure GIMP to resize the brush simply by scrolling the mouse wheel without holding modifier keys:

  1. Go to Edit > Preferences.
  2. In the left-hand menu, select Input Devices > Input Controllers.
  3. Under Active Controllers, double-click Main Mouse Wheel.
  4. In the configuration window, select Scroll Up and click Edit.
  5. Search for context-brush-radius-increase or Increase Brush Size, select it, and click OK.
  6. Select Scroll Down, click Edit, assign it to context-brush-radius-decrease or Decrease Brush Size, and click OK.
  7. Click OK on the Preferences window to save your settings.