The tolerance percentage determines how much visual difference is allowed before NerdTools considers it a significant change worth alerting you about.
Choosing a tolerance value
- Lower values (1-10%) — More sensitive. Good for pages that should remain nearly identical, like legal documents or critical landing pages.
- Medium values (10-25%) — Balanced. Suitable for most websites where minor variations are acceptable but major changes should be flagged.
- Higher values (25-50%) — Less sensitive. Useful for pages with dynamic content like news feeds or dashboards where some change is expected.
Default setting
The default tolerance is 15%, which works well for most use cases. Adjust based on your specific needs and how much natural variation your page has.