natwest digital regular saver - monthly interest rate calculation

OceanSound

The interest rate for Natwest digital regular saver as at 26 September was 5% gross / 5.12% AER. See: https://forums.moneysavingexpert.com/discussion/comment/79508939/#Comment_79508939

I believe it has remained the same.

On 01 November 2022, I can see that my NatWest digital regular saver account has been credited £3.98 with the description 'INTER BON [account number of digital saver]'. My balance has remained just over £1000 throughout October.

When I do the calculation, the result is: 

5% ----> (1000 x 100) / 5 = 1000 x 0.0500 = 50 ----> ---> (50 / 365) x 31 (number of days in October) = £4.24

How come only £3.98 interest was credited for October? 

surreysaver

First two days of October were a weekend. So they would have been paid at the beginning of October

RG2015

The 1st and 2nd of October fell at the weekend. Therefore your payment for September will have had an extra two days.

Your October calculation will be on 29 days not 31 days. I got £3.97 so you have an extra penny for having a bit more than £1,000 in there.