Pacing Calculator

What is the Pacing Calculator?

The Pacing Calculator works out the delay to insert between the end of one iteration and the start of the next, so your load test runs at a controlled, predictable rate instead of as fast as the application responds. Pacing is what keeps the workload steady when response times change, which lets you compare test runs fairly.

How it works

Pacing is the wait time you add between iterations so that, across all your users, the script produces exactly the target number of iterations over the test duration — without response time and think time alone driving an uncontrolled (and usually too high) throughput.

Formula to calculate pacing

Where:

• Target Iterations — Iterations the test must complete over the test period.
• Test Duration — Length of the test, in seconds.
• Users — Number of concurrent virtual users (threads).
• Response Time — Time taken to execute one iteration, in seconds.
• Think Time — Sum of all think times in the script, in seconds (0 if none).

Example of pacing calculation

A 10-minute (600-second) test runs 50 users, and the workload model requires 50 iterations over the test period.

Inputs

• Users = 50
• Target Iterations = 50
• Response Time = 5 seconds
• Think Time = 3 seconds
• Test Duration = 600 seconds

Step-by-step

1. Target Iterations × Test Duration ÷ Users = 50 × 600 ÷ 50 = 600 seconds
2. Subtract response time and think time: 600 − 5 − 3 = 592 seconds

Common mistakes to avoid

• Setting pacing to 0 by default — this lets response time variability drive throughput instead of your target workload.

• Forgetting that a negative pacing result means the users and iteration target are already saturating the available time; the calculator floors this at 0.

• Applying the same pacing value across scripts with very different response times, instead of recalculating per script.