How to use the Date Calculator
- Choose the starting and ending calendar dates.
- Turn on inclusive counting only when the final date itself should count.
- Use calendar days for elapsed spans and the weekday result for a basic Monday-to-Friday estimate.
How the calculation works
Day difference = (end date − start date) ÷ 86,400,000 msDates are converted to UTC midnight before subtraction, avoiding daylight-saving changes. Weekdays count Monday through Friday and do not remove public holidays.
Example calculation
From August 1 to August 25, 2026 is 24 elapsed calendar days when the end date is excluded. Inclusive counting adds one day. The weekday count ignores Saturdays and Sundays but not holidays.
How to interpret the result
Counting conventions matter. Deadlines often exclude the starting instant, while bookings or attendance periods may count both boundary dates. Confirm the convention required for your task.
Notes and assumptions
- The end date must be on or after the start date.
- Weekdays are Monday through Friday only.
- Public holidays, local weekends, and partial days are not included in the weekday logic.
Date Calculator questions
Does the result include the start date?
Elapsed-day counting begins after the start date. Enable the inclusive option to add the end date to the count.
Are holidays excluded from weekdays?
No. The weekday total removes Saturdays and Sundays only.
Can daylight saving time change the result?
No. The calculator compares UTC calendar dates rather than local timestamps.