Do unique CloudWatch Custom metric dimensions increase cost?

Question

I am trying to use custom metrics for product usage health analysis. Ideally, I would use a metric that has two dimensions - a dimension for the specific feature or context, and a dimension for let's say a user identifier. The generic metric would be used across different systems but use different dimensions to uniquely identify the context. The idea being to filter down and be able to sum metric counts for features/contexts and for users. Obviously the feature or context dimension would be limited to how many we use, but the user id dimension could expand uniquely for however many users we have. For instance, we could use generic Metric A, and it has feature and user_id dimensions; would there be a cost for each variation of Metric A with a different feature and a different user? Is there a better way to do metrics that are able to be tied to a unique identifier?

Thank you!

Didier Durand · Answer

Hi,

The pricing of custom CW metrics is described here: https://aws.amazon.com/cloudwatch/pricing/

```
All custom metrics and Detailed Monitoring charges are prorated by the hour 
and metered only when metrics are sent to CloudWatch. CloudWatch treats 
each unique combination of dimensions as a separate metric, even if the metrics 
have the same metric name. Detailed Monitoring pricing is based on the number 
of custom metrics, with no API charge for sending metrics. For example, if an EC2
 instance publishes 12 additional metrics with EC2 Detailed Monitoring, it would
 incur a charge of up to $3.60 per month for that instance at the highest price tier, 
or $0.24 per month at the lowest price tier.
```

Best,

Didier

Jsc · Answer

Hi,
yes a metric is defined by its namespace, metric name, list of dimensions (with values) and unit, so if you have multiple variations of a different feature in your dimension feature, it counts towards the number of metrics you pay for.

If you want to store information with high granularity, a possible solution is to store it in structured logs instead and use a contributor insight query to display in dashboards or alarm on.

Do unique CloudWatch Custom metric dimensions increase cost?

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