Use Case: What's the duration of a mortgage (€ 250,000.=) with yearly interest 2.25% and Monthly payment (€ 1,000.=) ?
Loan, Year-Interest 2.25%, Present Value € 250,000=, Monthly-Period payment € 1,000=, Future Value € 0,=,
Steps:

1. Set Calculate to No Calculation.
2. Set P to Month.
3. Set B to After.
4. Set N to 1. This is a dummy value, because the value has to be larger than 0.
5. Set I to 2.25.
6. Set PV to 250000.
7. Set PMT to -1000.
8. Set FV to 0.
9. Set Calculate to N - Duration.

Results in the value 28.03 shown in the Duration column under N.
Meaning: The duration of this loan will be 28 years and 11 days ( 0.03 * 365 ).

Use Case: What's the yearly interest percentage of a 30 year mortgage (250,000.=) annuity?
Loan, Duration 30 Years, Present Value € 250,000=, Monthly-Period payment € 1,000=, Future Value € 0,=,
Steps:

1. Set Calculate to No Calculation.
2. Set P to Month.
3. Set B to After.
4. Set N to 30.
5. Set PV to 250000.
6. Set PMT to -1000.
7. Set FV to 0.
8. Set Calculate to I - Interest.

Results in the value 2.62 shown in the Interest column under I.
Meaning: The year-interest is 2.62%.

Use Case: How many euros do you need to pay to get € 50,000.- after 5 year?
Saving, Duration 5 Years, Year Interest 1.75%, Present Value € 0.=, Future Value € 50,000.=.
Steps:

1. Set Calculate to No Calculation.
2. Set P to Month.
3. Set B to Before.
4. Set N to 5.
5. Set I to 1.75.
6. Set PV to 0.
7. Set PMT to 0.
8. Set FV to 50000.
9. Set Calculate to PMT - Period Payment.

Results in the value -797.14 shown in the Period Payment column under PMT.
Meaning: The monthly euro-payment is € 797.14.

Use Case: Buying a house with a mortgage, how many do you pay on Interest, Balance and in total?
Mortgage € 250,000.- for 30 Years, Monthly payment periods, Interest rate 1.89% per year.
Steps:

1. Click on the following URL FinCalc.php?test.

Results in the calculation for a PMT (Payment Period) of € 908.35 per month.
Please note the amortization graph.