Browser & Web Performance · Middle · Question 14 of 75
What does Total Blocking Time (TBT) measure in a lab test?
- ✓Correct answer: The sum of the parts of each long task beyond 50 ms between FCP and when the page becomes interactive
- 2The total time the network was blocked
- 3The total time spent in CSS parsing
Explanation
A 120 ms task contributes 70 ms. TBT correlates with INP and is useful because labs can't measure real interactions.