What is the exact interval for a monthly subscription, i.e. is it 30 days?
With a daily subscription, payments are triggered every 24 hours. A day is always 24 hours, so this is no issue. But what about months where the number of days differs?
The amount of time between a monthly billing interval is one month. This means 30 days for some months (April, June etc.), 31 days for others, and then 28 or 29 days for February. If a monthly subscription is created on the 15th of February, the next payment will be charged on the 15th March. If the billing interval for a subscription is every 2 months and it is created on the 15th of February, the next payment will be charged on the 15th April.
What about subscriptions purchased on the last day of the month?
If a subscription is purchased on the last day of the month, recurring payments will continue to be charged on the last day of the month. For example, if a $10 / month subscription is purchased on the 31st December, its next 4 payments will be charged on:
- 31st January
- 28th February (or 29th February for a leap year)
- 31st March
- 30th April
What about recurring payments on the 29th or 30th day of the month?
This system will also be used if the day a payment is normally charged is not the last day of the month, but it is on the 29th or 30th day of the month, and the next payment is due in February, which has no 30th day (and no 29th day in non-leap years).
For example, if a $10/month subscription is purchased on the 29th December 2012, the next 4 payments will be charged on:
- 29th January 2013- not the last day of the month
- 28th February 2013 – notice it has switched to the last day of the month as there is no 29th day in February when it is not a leap year
- 31st March 2013 (last day of the month)
- 30th April 2013 (last day of the month)
This logic ensures that a payment is made every month, and therefore, that one year includes 12 payments.