What's the unit for AppRunner's CPU Utilization?


Looking at the CloudWatch metric AppRunner > Instance metrics > CPU Utilization, I see that my instance is reaching up to 1000 of an unknown unit. Well, the question here is simple - what is the unit for CPU Utilization?

Here are my theories so far:

  • The official docs page on AppRunner metrics is not very helpful; their description is "The average CPU usage during one-minute periods."
  • The most obvious is percentage of CPU, but that should stop at 100%, so 1000% doesn't make much sense.
  • According to some other AWS products though, 100% = 1vCPU. This SageMaker question says 400% = 4 vCPUs. So 1000 would be 10 vCPUs.
  • But my instances are configured to use 1vCPU & 2 GB. So I'd still expect a max of 100, not 1000. Am I allowed to go above the max for brief amounts of time? Will I be charged extra if so?
  • Another theory is that this might be something to do with less than 1vCPU - like AWS Lambda's CPU throttling which lets you use less than 1vCPU. ie, 1000 = 1vCPU.
  • Finally, I might be doing something wrong. I'd be happy to share some details of my setup. I'm using maximum for aggregation statistic in Cloud Watch & only 1 instance is running.

But to sum up - does anyone know what the unit is for AppRunner's CPU Utilization?

asked 2 years ago762 views
2 Answers
Accepted Answer


The unit for CPU is percentage as you correctly stated. In the attached graph that shows "Graphed Metrics" I see that two labels have been selected. Could you try selecting only the second one (CPU Utilization) and let us know what you see? When two or more metrics are selected CloudWatch shows "various metrics" as the unit.

answered 2 years ago
  • Ah, thanks! Yes, I removed that & the unit become Percent! Not sure about the graph above (I've losted it now), but a newer one shows Percent & ranges from 0 - 200%. So if that SageMaker question is right, 200% would be 2vCPUs.


I am pretty sure it must be out of 1000. I have a 1 CPU AppRunner instance running... which is running only 1 instance at the moment, and in some load tests, it gets up to 1000 mark. Which wouldn't make sense if it was a %.

Enter image description here

answered 9 months ago

You are not logged in. Log in to post an answer.

A good answer clearly answers the question and provides constructive feedback and encourages professional growth in the question asker.

Guidelines for Answering Questions