How to estimate Azure Event Grid cost using Azure metrics

Question

I'm trying to build a cost model for my distributed system where Event Grid is a key piece.

Event Grid cost is based on millions of operations (0.561€ per million). See documentation.

This is the cost of my Event Grid on one production environment for one month:

These are the metrics for the same month:

Published Events + Delivered Events = 67.93M

67.93M * 0.561€ = 38.10€

This is ~3.5 less times than the actual cost. I have run same exercise on other environments with less workload and the result is pretty similar, between 3 and 4 times less than the actual cost.

Does anyone know what am I missing to estimate correctly the cost of my Event Grid instance?

Answer 1

Assuming that the number you have is the actual number of events.

Then there maybe 3 (at least) reasons that you are being billed for more:

• Are the events being delivered to multiple endpoints. You pay per delivery.
• Have some of your systems had an outage? You pay for retry events.
• Are your events larger than 64KB. For each message you pay per 64KB increment.

See: https://azure.microsoft.com/en-us/pricing/details/event-grid/?cdn=disable