How to calculate credit card interest accrued on transactions.

[BLuse]

I have a sheet with my credit card transaction and I'd like to get the interest accrued after each transaction but not necessarily every day. Additionally I want a table to keep track of transactions, payments and interest on a monthly basis..

I'm having trouble with getting the accurate interest calculated. The problem is that I can't simply average the transactions an multiply by the interest rate because not every day has a transaction so the missing days aren't accurately being included in the average.As in the example below, the formula should calculate interest on 9,460.30 for all the days between 1/9 and 1/19 and starting accruing interest on 14,560.30 on 1/20 to 1/25 and so on.

Date	Amount	Balance
1/9/2023	75.82	9,460.30
1/20/2023	5,100.00	14,560.30
1/26/2023	134.91	14,695.21
2/3/2023	760	15,455.21

 

[Rijnsent]

Assuming your "Date" cell is A1, you could do:
D2: =A3-A2 -> gives the amount of days that that balance accrues interest
E2: =(((1+10%)^(1/365))^D2-1)*C2 -> interest for those days on that amount. I don't know what your daily interest is, (1+10%)^(1/365) assumes cumulating to a yearly rate of 10% in 365 days (interest on interest)
F2: =SOM($E$2:E2)
And drag all these formulas down. You can probably squeeze it all into one massive formula, but I wouldn't do that.

Cheers