# Instant Interest Manual – Custom Calculation Tab

The Custom Calculation tab can be used for jurisdictions other than those in the Instant Interest rate table or for rates which for some reason vary from those carried in the rate table. The Custom Calculation tab is accessed by clicking on the third tab and appears as follows: The input areas consist of three fields and one table. The three fields are as follows:

Taxpayer is a comment only field (that is, it has no effect on the calculations) that can be used to document the taxpayer for the interest schedule. This is useful for worksheets which are saved for reuse later or printed.
Tax Jurisdiction is the tax jurisdiction for which interest is being calculated. On the Custom Calculation screen, the Tax Jurisdiction field is a comment only. The rates stored in the Instant Interest rate file are not used, even if the jurisdiction entered matches one in the table. However, you can set up a calculation on either the Standard Input or Easy Calculation tab and then switch to the Custom Calculation tab to made adjustments to the rate information loaded from the Instant Interest rate file.
Thru Date is the date (in MM/DD/YY format) through which the interest is to be calculated.

The Custom Calculation table can be used to enter either positive or negative amounts for any date. Positive amounts indicate amounts due, including additional assessments. Negative amounts can be used to indicate payments made. In the example above, there is a \$100,000 amount due on 3/15/91, a \$30,000 payment made on 7/15/92, and an additional assessment of \$25,000 on 8/13/93.
The Custom Calculation table has nine columns:

A line number;
A Del(ete) button;
Date is the date from which to calculate the amount due/payment made or when the change in interest rate, calculation method, etc. was effective;
Amount is the dollar value of the amount due/payment made;
Rate is the percentage rate at which to calculate interest;
Method is the compounding method to be used for calculating interest (such as simple interest or daily compounding);
Basis is the means of calculating the period of time for which interest is due if it is other than calendar days;
Days/Yr is the number of days treated as a calendar year if it is not the same as the number of days actually in the calendar year;
The Notes field may be used to annotate entries in the table.

The Del(ete) button is used to delete a line from the table. When you point at the Delete button and click on it, you will receive a prompt asking you if you really want to delete that line (provided there is data on that line).
The following are valid values for entries in the Method column:

 SIM Simple interest DAI Daily compounding MON Monthly compounding QTR Quarterly compounding ANN Annual compounding

In the Basis column, enter "M/D" if partial months are calculated as the number of whole months plus the number of days in a partial month. Otherwise, leave the entry blank. For example, in a non-leap year, 01/01 through 03/15 would be treated as 2 months and 15 days if the Basis is "M/D" and as 74 days if Basis is left blank.
In the Days/Yr column, enter "360" if taxes for partial periods are calculated based on having 360 days in the year rather than the number of days (365 or 366) actually in the year.
The Custom Calculation tab also has two command buttons, as follows:

The Calculate button is used to generate and display an interest schedule based on the values in the current worksheet.
The Print button is used to generate and print an interest schedule based on the values in the current worksheet.

The command buttons that appear above the Custom Calculation tab ("New", "Open", etc.) are common to all four of the basic input forms and are described under Common Input Form Buttons.