Glossary

TBT (Total Blocking Time)

A metric measuring the total time the main thread was blocked long enough to prevent input responsiveness.

What is TBT (Total Blocking Time)?

Total Blocking Time (TBT) measures the total amount of time between FCP and TTI where the main thread was blocked for long enough to prevent input responsiveness (tasks longer than 50ms).

Performance Thresholds

  • Good: < 200ms
  • Needs Improvement: 200ms - 600ms
  • Poor: > 600ms

Key Takeaways

  • 1.TBT (Total Blocking Time) is important for website performance and SEO.
  • 2.You can measure it using tools like BulkAudit and Google Lighthouse.
  • 3.Improving this metric can lead to better user experience and search rankings.

Learn More

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