Day of Week
Determine which day of the week any date falls on.
About Day of Week
Because the calendar repeats every seven days, dividing the day number by seven reveals the weekday of any date. Knowing the weekday helps with scheduling, historical dates and planning around weekends.
Formula
Day of Week
Weekday derived from the day count modulo 7 (Monday to Sunday)
- Monday
- Week number 1 maps to Monday through number 7 for Sunday
Worked example
With the default values below, Day of Week returns Weekday of Thursday. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Year
- 2,025
- Monthaccepts 1–12
- 12
- Dayaccepts 1–31
- 25
Results
- Weekday
- Thursday
- Weekday Number
- 4
- Weekend?
- No
Step by step
- 1Values used
- 2Day of Week
- 3Weekday= Thursday
- 4Weekday Number= 4
- 5Weekend?= No
Assumptions and limits
- The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to whole numbers, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
How is Day of Week calculated?
Weekday derived from the day count modulo 7 (Monday to Sunday) Because the calendar repeats every seven days, dividing the day number by seven reveals the weekday of any date.
Why does Day of Week matter?
Knowing the weekday helps with scheduling, historical dates and planning around weekends.
What values do I need to enter?
This calculator takes 3 inputs: Year, Month, Day. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.