### Question

Scheduled payment intervals are to be formatted according to ISO 8601 Durations. For example, see the CDS schema BankingScheduledPaymentInterval.

If `interval`

= `P3M`

, and there is no specific day for the payment, then is `dayInInterval`

= `P90D`

, based on processing the payment always on the last day of the interval.

### Answer

A `dayInInterval`

value of `P90D`

would indicate the last day of a three month interval, if all three consecutive months had 30 days in them.

If the `dayInInterval`

value is greater than the number of days in the interval, the payment takes place on the last day of the interval, so `P100D`

would indicate the last day. The value `P0D`

also indicates payment is on the last day of the interval.

### Question

If `interval`

= `P3M`

, a specific day is the 10th of the month, then what is the correct value for `dayInInterval`

?

### Answer

If the payment is made on the 10th day once every 3 months, then the `dayInInterval`

is `P10D`

.

If the payment is instead made on the 10th day of every month, then the `interval`

is `P1M`

and the `dayInInterval`

is `P10D`

.

Further examples are available in the knowledge base article Scheduled Payment Recurrence and intervals.

### Question

Our scheduled payment intervals begin on the day the first payment is made. In this case, the `dayInInterval`

value is always `P1D`

. The first payment is on the first day of the interval, and consequently all other payments are also on the first day of the interval. Is that the correct use of this field?

### Answer

That is the correct interpretation of the `dayInInterval`

field. The default is `P1D`

for this reason. See the `dayInInterval`

field description in BankingScheduledPaymentInterval. The `dayInInterval`

field was introduced in response to a request to make the next payment date optional.

## Comments

1 comment

`dayInInterval`

'`P10D' or '10' in the example above?`

`if a payment is made weekly on a Monday, is this correct?`

Please sign in to leave a comment.