For a membership, choose when members pay: from their own start date or on a fixed day of the month. Configure this in Finance → Offerings → your membership → step Plan, under Invoice timing → Invoice cycle.
Option 1: From each member's start date
Each member pays on the day their membership started. If someone starts on 15 October, they pay on 15 October, 15 November, 15 December, and so on.
There is no prorated amount with this option. The member pays one full installment immediately on registration.
Option 2: On a fixed day of the month
All members pay on the same day, for example the 1st of the month. Enter that day under Day of the month.
If a member registers between payment dates, there is a short initial period until the fixed day. This is called the prorated amount. Under First payment choose how the member pays it.
Prorated amount only
The member pays only the prorated amount immediately on registration. The first full installment then follows on the fixed day.
Example (payment day 1, registration on 15 October):
15 October: the member pays for 15 through 31 October.
1 November: the member pays the full November installment.
Prorated amount plus first full installment
On registration, the member pays the prorated amount and first full installment together. Afterwards, they pay normally on the fixed day.
Example (payment day 1, registration on 15 October):
15 October: the member pays for 15 through 31 October plus the November installment.
1 December: the member pays the next full installment.
Registration just before the fixed day
If you choose Prorated amount only and someone registers just before the fixed day, they pay twice in quick succession. Avoid this with Include next installment if it starts soon. Under Number of days specify the maximum number of days. If the next installment starts within that period, the member pays it as part of the first payment.
Good to know
The first payment always occurs on registration. Access begins on the agreed start date.
Does your fixed day not occur every month (for example the 31st)? Under If the day does not exist then choose Last day of the month or Next month. This is not an issue if you choose a day from 1 through 28.
Before saving, you see an example of what the member pays now and when subsequent installments fall.
See also: Creating a service or membership (setting up offerings).