A billing period defines the interval used to charge recurring fees and generate invoices. The first billing period starts on the day the customer is created. If invoicing is enabled, an invoice is generated at the end of each billing period. PortaBilling supports the following billing periods:
- Monthly – billing periods follow calendar months (from the 1st to the last day of the month).
For example, if a customer is created on March 10th, the first billing period covers March 10th through March 31st. The next covers April 1st through April 30th, and so on.
- Monthly (anniversary) – each billing period runs from day N of the current month to the day before day N of the following month, where N is the day the customer was created.
For example, if a customer is created on March 19th, each billing period runs from the 19th of the current month through the 18th of the following month.
If a customer is created on the 29th, 30th, or 31st, the system uses the 28th as the end day to avoid end-of-month inconsistencies. For example, if a customer is created on March 30th, the first billing period covers March 30th through April 28th. The next covers April 28th through May 28th, and so on.
- 30 days – each billing period is exactly 30 days, regardless of calendar months.
For example, if a customer is created on March 20th, the first billing period covers March 20th through April 18th; the second covers April 19th through May 18th, and so on. This option is useful for subscription-based services where a subscription is charged every 30 days, instead of the varying length of calendar months (28–31 days).
- Semimonthly – covers periods from the 1st to the 15th, and from the 16th to the last day of the month.
For example, if a customer is created on March 10th, the first billing period covers March 10th through March 15th. The next covers March 16th through March 31st, and so on.
- Weekly – billing periods follow calendar weeks (Monday through Sunday).
For example, if a customer is created on Tuesday, the first billing period covers Tuesday through Sunday. The next covers Monday through Sunday, and so on.
- Daily – covers a 24-hour period.
For example, if a customer is created on March 11th, the first billing period covers March 11th. The second covers March 12th, and so on.
Each billing period is calculated in the billing time zone configured for the respective customer or sales agent.
For example, with a weekly billing cycle, the billing period starts at 00:00 on Monday in the relevant time zone. For a customer in Los Angeles, it starts at 00:00 Monday Pacific time; for a customer in Singapore, it starts at 00:00 Monday Singapore time. Both billing periods cover 7 days (168 hours), but when viewed in a common time zone (for example, UTC or the administrator's time zone), the actual time range differs.
