=PMT(rate, nper, pv, [fv], [type]) returns the payment per period for a loan with a fixed rate:
- rate is the rate per period: an annual 6.9% paid monthly is
6.9%/12.
- nper is the number of payments: 5 years monthly is
5*12.
- pv is the amount borrowed now; fv is what's left at the end (0 for a loan, the target for savings).
The two must match: monthly rate with monthly periods. Mixing an annual rate with monthly periods is the most common PMT mistake, and gives a payment far too high.
Excel's finance functions follow the cash: money you receive is positive, money you pay is negative. Borrowing 28,000 is +28,000, so PMT returns a negative payment. Put a minus before the loan, -B1, to see the payment as a positive number.