Week and day number of a date

Online tool for calculating week number and day of the week based on a date.

Week Number Calculator

Choose a date to find out its week number, as well as the corresponding day of the week. You can view the day's info directly by clicking here.

Result

Saturday, December 20, 2025 is part of week 51, which runs from Monday, December 15, 2025 to Sunday, December 21, 2025.

Calculation form