daily interest

[payments]

i have been stumped

I have a debitor who owes $379 each week
With a default interest of 13.5% calculated daily

how do i set a formula to calculate what the interest is per outstanding
amount per week
this also needs to be added onto the next weeks behind payment so it balloons

first payment due 21/4/05 $379 18 days late
second paymnet 28/4/05 $379 11 days late
thrid payment 5/5/05 $379 4 days late

first payment paid 9/5/05 of $1137

 

[joeu2004]

I have a debitor who owes $379 each week
With a default interest of 13.5% calculated daily
how do i set a formula to calculate what the interest is
per outstanding amount per week

If column A is the due date and B is the paid date, the
amount of interest is:

round(fv(13.5%/365, B1-A1,, -$379), 2)

this also needs to be added onto the next weeks behind
payment so it balloons

If column C is the amount paid, E is the amount of interest
and D is the outstanding balance (where D1 is the previous
outstanding balance), then:

E2: =round(if(isblank(B2), FV(13.5%/365, TODAY()-A2,, D1),
FV(13.5%/365, B2-A2,, D1)), 2)
D2: =D1 + E2 - C2

Note: Alternatively you could populate column B with =TODAY()
and replace if() with simply fv(...,B2-A2,...).