Create Late Payment Interest Calculator in Excel and Download for Free

Here’s an overview of the late interest calculator we’re building in the article. You can follow along or download the template to use immediately.

Download the Calculator

You can download the free Excel template from here.

Late Payment Interest Calculator.xlsx

How to Make a Late Payment Interest Calculator in Excel

We’ll use the following dataset that represents some buyers’ invoice details-their invoice dates, due amounts, contacted payment periods, contacted payment dates, and interest rates.

We have added two new columns to find the over-days and due interest.

Let’s start with the overdue duration.

Select cell G5.
Copy the following formula in it:

=F5-C5-E5

Hit Enter to get the output.

Drag down the Fill Handle icon over the cells G6:G9 to copy the formula.

Now let’s go for the due interests using a formula.

In cell I5 copy the following formula:

=(D5*H5)*G5/365

Press the Enter button.

Drag down the Fill Handle icon for the cells I6:I9 to get all the other due interests.

You will get all the interests.

Things to Remember

Don’t forget to divide the day number by 365 because the interest rate is given in per year format.
Make sure that the cells containing rates are in Percentage format.