Late Payment Interest Calculator to Calculate Interest on Overdue Invoices

Late Payment Interest Calculator Sign

This Late Fee Calculator will help you to quickly calculate the interest penalty on overdue invoices.

In addition to calculating the late fee, the calculator will also calculate the daily penalty interest rate and the total amount due.

Plus, if you name and save your entries under the "Data" tab, you can quickly update the penalty interest on future billing statements just by changing the settlement date.

Read more ...

Also on this page:

Late Payment Interest Calculator

Calculate late payment interest on past due invoices.

Special Instructions

Learn More

Selected Data Record:

A Data Record is a set of calculator entries that are stored in your web browser's Local Storage. If a Data Record is currently selected in the "Data" tab, this line will list the name you gave to that data record. If no data record is selected, or you have no entries stored for this calculator, the line will display "None".

DataData recordData recordSelected data record: None
Amt due:Amount due:Past due amount:Past due amount:

Past due amount:

Enter the past due amount, excluding any previous interest penalties, without the dollar sign or any comma.

Rate:Penalty APR:Penalty annual interest rate:Penalty annual interest rate:

Penalty annual interest rate:

Enter the penalty annual interest rate expressed as a percentage, but without the percent sign (for 6.5%, enter 6.5).

Payment due date:

Payment due date:

Select the month and day, and enter the 4-digit year of the date the payment was originally due.

Settlement date:

Settlement date:

Select the month and day, and enter the 4-digit year of the date to calculate late fees for.

Late days:Past due days:Number of days past due:Number of days past due:

Number of days past due:

If you entered a date in the previous line, the number of days past due will be calculated for you. Otherwise, you can enter a number of past days in this field and the calculator will update the month, day, and year in the previous line for you.

Late fee:Penalty interest:Late payment interest:Late payment interest:

Late payment interest:

This is the amount of the simple interest that has accrued between the payment due date and the settlement date.

Total due:Total due:Total due:Total due:

Total Due:

This is the late payment amount plus penalty interest as of the settlement date.

Daily rate:Daily penalty rate:Daily penalty rate:Daily penalty rate:

Daily penalty rate:

This is the daily penalty interest rate used to calculate the late fee.

If you would like to save the current entries to the secure online database, tap or click on the Data tab, select "New Data Record", give the data record a name, then tap or click the Save button. To save changes to previously saved entries, simply tap the Save button. Please select and "Clear" any data records you no longer need.

Help and Tools


How to Calculate Late Payment Interest

How To Calculate Late Payment Interest

Before you can calculate interest on an overdue invoice, you must first determine the penalty APR. The rate you can charge varies from state to state, so be sure to check with your accountant for your state's usury limits.

Once you have determined the penalty APR, use the following steps to calculate interest on overdue invoices:

  1. Determine the amount that is past due. For example, if you billed $1,000 to a customer with net-30 terms, and 30 days has passed without payment, the past due amount would be $1,000.
  2. Calculate the daily penalty rate by dividing the annual penalty rate by 365. For example, if the annual rate is 8%, convert the percentage to a decimal (8% = 0.08) and divide by 365 to get a daily rate of 0.00021918 (0.0192%).
  3. Determine the number of days the invoice is past due. For example, if the invoice was due on June 1st, and the new statement date is July 1st, the invoice would be 30 days past due.
  4. Multiply the daily rate by the number of days past due, and then by the past due amount to get the total late fee. For example, if the daily rate is 0.00021918 and the $1,000 invoice is 30-days overdue, the total late fee would be $6.58 (0.00021918 x 30 x $1,000).

If the next billing term passes without receiving the payment for the past due invoice, repeat the above steps for the next billing cycle. For example, if the $1,000 invoice is not received by August 1st, the late payment fee would increase to $13.37 (0.00021918 x 61 x $1,000).

Adjust Calculator Width:

Move the slider to left and right to adjust the calculator width. Note that the Help and Tools panel will be hidden when the calculator is too wide to fit both on the screen. Moving the slider to the left will bring the instructions and tools panel back into view.

Also note that some calculators will reformat to accommodate the screen size as you make the calculator wider or narrower. If the calculator is narrow, columns of entry rows will be converted to a vertical entry form, whereas a wider calculator will display columns of entry rows, and the entry fields will be smaller in size ... since they will not need to be "thumb friendly".

Show/Hide Popup Keypads:

Select Show or Hide to show or hide the popup keypad icons located next to numeric entry fields. These are generally only needed for mobile devices that don't have decimal points in their numeric keypads. So if you are on a desktop, you may find the calculator to be more user-friendly and less cluttered without them.

Stick/Unstick Tools:

Select Stick or Unstick to stick or unstick the help and tools panel. Selecting "Stick" will keep the panel in view while scrolling the calculator vertically. If you find that annoying, select "Unstick" to keep the panel in a stationary position.

If the tools panel becomes "Unstuck" on its own, try clicking "Unstick" and then "Stick" to re-stick the panel.