Can’t Change the Brush Size in GIMP? [How to Fix It]

If you regularly edit and do touch-ups on photographs, you are likely very familiar with Photoshop. However, for those who may be short on funds and looking for a similar program to help them with all sorts of tasks from adding painting to photos to retouching to converting, GIMP is a fantastic program that is free to use and capable of editing photos and working with a variety of extensions.

If you are trying to make sure that the image you are editing looks as professional as possible, then probably the most important thing to master is changing the brush size in GIMP. However, if you are new to the program, you may not be sure how to change it, and with GIMP one of the bugs is that sometimes the brush will be frozen, and you will not be able to change the size. If this has happened to you and you are frustrated, read on to find out how to fix it.

How Do I Change the Brush Size in GIMP Quickly?

If you have opened your GIMP program and are trying to edit a photo, but find that you cannot change the brush size or that it seems to be frozen, do a quick test with the following steps:

  1. Locate the Shift key on your keyboard. Most keyboards have two Shift keys, located on the lower right and lower left of the keyboard. It does not matter which you use, so find the one that feels most comfortable.
  2. Next, locate the square brackets. They look like this: [ ], and are usually located on the top right of the keyboard underneath the button with the plus and equals signs.
  3. Once you have located both keys, press them at the same time. As stated, this is a quick and big fix. Once you press both these keys the brush size will grow 10 times its size.

Now that you know how to quickly change the size of your GIMP brush, take a look below to see how to do it more gradually.

How Do I Change the Brush Size in GIMP Gradually?

Trying a quick fix like the one above is good if the brush seems to be frozen or to test things out. However, if you are in the middle of a project, a gradual increase is the preferred method for those little details you are trying to edit. Once you have opened up GIMP take the following steps:

  • If you want to make your brush smaller, press the left-hand square bracket. It will look like this: [.
  • If you want to make your brush bigger, press the right-hand square bracket. It will look like this: ].

This is the simplest and quickest way to change the brush size and having it become second nature will be incredibly beneficial to you.

How Do I Create New Brush Sizes?

Now you know how to drastically change the brush size and how to do it incrementally, but what about when either of these options does not work for what you are trying to do, and you need a special-sized brush that you want to get to quickly? In that case, it is entirely possible to create a new brush size by doing the following:

  1. Open the brush panel. To do this press the Control, Shift, and B buttons on your keyboard simultaneously.
  2. Once the brush panel is open click on the “Create New Brush” button. It will be the button second from the left in the row of buttons located at the bottom of the panel.
  3. Customize the brush however you want. The options available to you include radius, spikes, hardness, aspect ratio, angle, and spacing. To customize each of these, click the arrow button to the right of each to increase or decrease.

Now that you know how to customize brush sizes, you can make as many as you need, and move between them with one click as opposed to having to smash the bracket buttons repeatedly.


GIMP is a great photo editing program. Though it is not as well-known as PhotoShop, it performs many similar functions and is capable of creating professional and polished products. To use it properly, it is important to know how the brush works, and how to move between different brush sizes smoothly and efficiently.

The quickest way to change the brush size is to press the shift and bracket keys at the same time. This will increase the size of your brush by ten. However, for a slower change in size, press the left-hand bracket to decrease, and the right-hand bracket to increase. To customize a brush size, go into the brush panel, create a new brush, and adjust the settings to your preference.