@RajeshSwarnkar-0193 - Thanks for reaching out .
Looks like its aligned to your invoice period.
If you have a Pay-As-You-Go, MSDN, or Visual Studio subscription, your invoice billing period might not align to the calendar month. For those subscription types and resource groups, you can create a budget that's aligned to your invoice period or to calendar months.
To create a budget aligned to your invoice period, select a reset period of Billing month, Billing quarter, or Billing year. To create a budget aligned to the calendar month, select a reset period of Monthly, Quarterly, or Annually."
Take a look at this document for more reference : Create Budgets
Hope this helps.
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