PyCharm Low Memory Warning: How to Increase the Heap Size

How to fix it

Try these in order — the most common fix is first.

1. 1. Change memory settings

   Copy steps
   1. Help | Change Memory Settings (or Settings | Memory Usage)
   2. Enter a larger value, or accept the suggested one from the warning's Adjust memory options
   3. Click Save and Restart
   Did this fix it? Yes No

2. 2. Monitor usage

   1. Settings | Memory Usage, enable Show Memory Indicator
   Did this fix it? Yes No

3. 3. Toolbox App or won't start

   Copy steps
   1. Toolbox: instance settings icon | Settings | Configuration | Maximum heap size
   2. Standalone: copy the default JVM options file and edit -Xmx in the copy
   Did this fix it? Yes No

Symptoms

IDE lags, freezes, or shows the Low Memory notification.

Why it happens

• Heap (-Xmx) too small for project size
• Many plugins or large projects

This guide also covers

• pycharm increase memory
• pycharm low memory warning
• pycharm slow
• pycharm xmx

The same problem in other apps

All slow, laggy or resource-hungry guides →

• VS Code High CPU Usage (VS Code)
• Sublime Text Slow or Glitchy Display: Indexing and GPU Settings (Sublime Text)
• Cursor Slow, High CPU or Memory Usage (Cursor)

Other PyCharm errors

• PyCharm Invalid Python Interpreter / Invalid Environment
• PyCharm No Python Interpreter Configured for the Project
• PyCharm Unresolved Reference: Installed Package Not Recognized
• PyCharm Cannot Install or Find a Package
• PyCharm Conda Executable Not Found / Conda Environment Not Detected
• PyCharm Indexing Takes Forever / Stuck on Analyzing Project
• PyCharm Invalidate Caches / Restart: When and How
• PyCharm Debugger Not Working / Breakpoints Not Hit