Up to 140m2
The range is largely dependent on several environmental factors but there's steps you can take to reduce interference.
If you need extenders in your home, they should be 50ft apart from one another at most. This is the sweet spot that ensures they can provide a signal overlap and keep all of your device connections strong.
If you need more help with this, the eero app will take you through the best placement instructions to ensure you're getting the most out of your set up.