What is the IPMT Function?
=IPMT(rate, per, nper, pv, [fv], [type])
arguments:
rate - The interest rate per period.
per - The payment period of interest.
nper - The total number of payment periods.
pv - The present value, or total value of all payments now.
fv - [optional] The cash balance desired after last payment is made.
type - [optional] When payments are due.
IPMT formula for different payment frequencies (weeks, months, quarters, yearly)
Weekly:
=IPMT(6%/52, 1, 2*52, 20000)
Monthly:
=IPMT(6%/12, 1, 2*12, 20000)
Quarterly:
=IPMT(6%/4, 1, 2*4, 20000)
Semi-annual:

What is difference between PMT and IPMT in Excel?
Whereas the PMT function tells you how much each payment
(EMI) will be, the PPMT function tells you how much of the principal is being
paid in any given pay period (EMI).