Calculating average using a Histogram metric

Question

I am generating a Histogram using a prometheus client. The metric name is retrieve_stripe_subscription_latency_ms. Since Histogram generates additional metrics with suffixes _sum and _count, can I calculate the average using the below query in Grafana?

sum(retrieve_stripe_subscription_latency_ms_sum)/sum(retrieve_stripe_subscription_latency_ms_count)

Answer 1

I think official Prometheus documentation address this. Having your metric name:

To calculate the average [...put here a metric meaning...] during the last 5 minutes from a histogram or summary called retrieve_stripe_subscription_latency_ms, use the following expression:

rate(retrieve_stripe_subscription_latency_ms_sum[5m])
/
rate(retrieve_stripe_subscription_latency_ms_count[5m])