# bill/BillingPeriodStartDate #level100 #cur #finops #curfield Identify the beginning of the billing period the row in the CUR refers to. Most of the time this is the first day and hour of the month. ## Source - Category: [[Billing details]] - [AWS documentation](https://docs.aws.amazon.com/cur/latest/userguide/billing-columns.html) ## Relevant notes [[lineItem_UsageEndDate]] is the twin but for the end of the billing period ## Notes - Format is `YYYY-MM-DDTHH:mm:ssZ`. - Timezone is UTC