How To Use the Bucket Fill Tool in GIMP {Complete Guide}

large featured bucket

In today’s tutorial, you’ll learn everything you need to know about using the Bucket Fill tool in GIMP. If you’re ready… let’s do it!

Table of Contents

What Is the GIMP Bucket Fill Tool?

paint bucket

Photo by David Waschusch

The Bucket Fill tool is one of many paint tools available to you. It’s designed to “fill” a selection, your canvas, or even line art intelligently.

Filling in a selection is essential for creating shapes since GIMP doesn’t have a native shape tool. Changing the color of a blank canvas can be quickly done with the Bucket tool too. If you have line art that you’d like to color, well, you can fill it with this tool as well.

You’re not limited to just solid colors either. With the right Tool Options set, you can fill with a pattern!

Tool Options

Click the image to enlarge.

Like any other tool, you have a variety of settings to choose from in the Tool Options. First, grab your Bucket Fill tool from the toolbar or use the keyboard shortcut, Shift + B. Once you do, the Tool Options will change based on the features for the bucket. If you can’t see the Tool Options, go to Windows > Dockable Dialogs > Tool Options to reveal the panel.


The first setting to consider is “Mode.” This sets the Bucket tool’s blending mode and determines how the pixels are applied based on the Mode chosen.


Use this to decrease the transparency of the color fill.

Fill Type

Affected Area

Finding Similar Colors

Use this to decrease the transparency of the color fill.


You’ll use this mainly for images vs. filling an empty layer or selection with color. Increasing the Threshold will add more of the color vs. a lower setting.

Fill by

Use this to target specific color channels within the image. The components available are Composite, Red, Green, Blue, Alpha, HSV Hue, HSV Saturation, HSV Value, LCh Lightness, LCh Chroma, and LCh Hue.

This setting is complex and challenging to understand. Suppose you’ve chosen the Blue channel and click on any pixel in your image. The tool is going to search for contiguous pixels similar to the blue channel to fill with. Depending on matching colors and the Threshold setting will determine if the colors are replaced.

How To Use the Bucket Fill Tool

create shapes

Created for the “Create Shapes” tutorials.

Using the Bucket Fill tool is straightforward. Select your foreground color of choice, update the settings accordingly, and click inside a selection or on the canvas. Voila! Your foreground color has been filled into the space.

Pro Tip

Instead of filling with the Bucket Fill tool, you have three other options.

Line Art Detection

owl line art

Let’s say you’ve created a line art illustration you’d like to fill in with color. Using the Bucket Fill tool is the quickest way to do so. Once upon a time, using it would fill your entire canvas with the colors of your choice. Since GIMP 2.10.10, the tool is much smarter than it was in earlier versions.

Now, when you click in-between some lines, the tool confines the color fill to what it perceives to be a specific area. It does this by analyzing the lines, and if it realizes there’s a gap where the line should extend to, it will stop the color from bleeding out.

This is perfect when you want to color different sections of the line art with different colors.

Tool Options

settings for line art

When you activate this setting in the Options panel, additional settings will be revealed. Set these according to your preference for better results.

What's Next?

If you’re a photographer, you will rarely, if ever, use the Bucket tool. On the other hand, if you’re a graphic designer, the Bucket tool will be your new best friend. If you’d like to expand your graphic design knowledge, check out these advanced tutorials.

Like this article? If so, please share!

Leave a Reply

Your email address will not be published.

This site uses Akismet to reduce spam. Learn how your comment data is processed.