When you are subscribed to a paid monthly tier (S1, S2, S3 or S4 tiers only) for either the Microsoft Translator Text API or Translator Speech API in the Azure portal, you can get a day-by-day report of your consumption. There is a 24-hour delay between the actual consumption and when it is displayed in the report.
At this time, subscribers to the free monthly subscription tiers (F0 tier) do not have the ability to view a consumption report.
To view the report:
1) Visit https://account.windowsazure.com/Subscriptions
2) Choose the name of your Azure subscription
3) Choose "Download usage details"
4) Choose "Download usage"
You will receive a CSV file containing your daily consumption, one line per day per service.
To see the Microsoft Translator API consumption, filter by Meter Category = Cognitive Services.
You can also get a graph for the current billing period, in the Overview section.