How to increase IDE memory limit in IntelliJ IDEA on Mac?

Current version: Help | Change Memory Settings:

Since IntelliJ IDEA 15.0.4 you can also use: Help | Edit Custom VM Options...:

This will automatically create a copy of the .vmoptions file in the config folder and open a dialog to edit it.

Older versions:

IntelliJ IDEA 12 is a signed application, therefore changing options in Info.plist is no longer recommended, as the signature will not match and you will get issues depending on your system security settings (app will either not run, or firewall will complain on every start, or the app will not be able to use the system keystore to save passwords).

As a result of addressing IDEA-94050 a new way to supply JVM options was introduced in IDEA 12:

Now it can take VM options from ~/Library/Preferences/<appFolder>/idea.vmoptions and system properties from ~/Library/Preferences/<appFolder>/idea.properties.

For example, to use -Xmx2048m option you should copy the original .vmoptions file from /Applications/IntelliJ IDEA.app/bin/idea.vmoptions to ~/Library/Preferences/IntelliJIdea12/idea.vmoptions, then modify the -Xmx setting.

The final file should look like:

-Xms128m
-Xmx2048m
-XX:MaxPermSize=350m
-XX:ReservedCodeCacheSize=64m
-XX:+UseCodeCacheFlushing
-XX:+UseCompressedOops

Copying the original file is important, as options are not added, they are replaced.

This way your custom options will be preserved between updates and application files will remain unmodified making signature checker happy.

Community Edition: ~/Library/Preferences/IdeaIC12/idea.vmoptions file is used instead.

[Updated Aug 2021 since the JetBrains UI has changed]

Helpful trick I thought I'd share on this old thread.

You can see how much memory is being used and adjust things accordingly using the Memory Indicator

Right click in the bottom most taskbar area and select the Memory Indicator item

It shows up in the lower right of the window.

For IDEA 13 and OS X 10.9 Mavericks, the correct paths are:

Original: /Applications/IntelliJ IDEA 13.app/Contents/bin/idea.vmoptions

Copy to: ~/Library/Preferences/IntelliJIdea13/idea.vmoptions

Here is a link to the latest documentation as of today http://www.jetbrains.com/idea/webhelp/increasing-memory-heap.html