Calculate days overdue or days past due: enter the due date and today’s date to count calendar or business days late, with optional late-fee estimates.

Starts as today on your device. Change it to count to another date.

Day counting and grace period

Blank means zero; subtract this count before fees begin.

Related Calculators

Days Overdue Formula

The following formula is used to calculate the number of days overdue for a given due date and current date.

O = max(0, (C - F) / 86400000)

Variables:

  • O is calendar days overdue before any grace period
  • C is the as-of UTC calendar timestamp in milliseconds
  • F is the due-date UTC calendar timestamp in milliseconds

For calendar days overdue, subtract the due-date UTC calendar timestamp from the as-of timestamp, divide by 86,400,000, and use zero if the deadline has not passed. The optional weekday basis excludes weekends; a grace period reduces chargeable fee days.

What is Days Overdue?

Days overdue refers to the number of days that have passed since a specified due date. This metric is commonly used in various fields such as finance, library services, and project management to track the timeliness of payments, returns, or task completions. Knowing the number of days overdue can help in assessing penalties, interest, or other consequences associated with late actions.

How to Calculate Days Overdue?

The following steps outline how to calculate the Days Overdue.

  1. First, determine the current date (C).
  2. Next, determine the due date (F).
  3. Next, calculate the difference between the current date and the due date using the formula O = max(0, (C – F) / 86400000).
  4. Finally, calculate the Days Overdue.
  5. After inserting the values and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

Current Date (C) = 2023-10-10

Due Date (F) = 2023-10-01