How to Count the Days Until a Date

Formula

days left = target date − start date

full weeks = ⌊|days left| / 7⌋

remaining days = |days left| − 7 × full weeks

• target date: the day you count to, such as an exam, a holiday or New Year’s Day
• start date: the day you count from, usually today
• |days left|: the number of days without its minus sign
• ⌊ ⌋: rounding down

February has 29 days in leap years. Weekends and holidays are not removed; every calendar day counts.

Step-by-step example

The days from 13 September 2026 to New Year’s Day, 1 January 2027:

1. Days left: 2027-01-01 − 2026-09-13 = 110 days.
2. Full weeks: ⌊110 / 7⌋ = 15 weeks.
3. Remaining days: 110 − 7 × 15 = 5 days.

The result: 110 days, or 15 weeks and 5 days, to New Year’s Day.

Why the target day is not counted

Days left is the difference between two dates. If the target is tomorrow, 1 day is left; on the target day itself the counter shows 0. From 13 September 2026 to 14 September 2026 is 1 day, and from 13 September to 13 September is 0 days. If you want to count the target day too, add 1.

When the date has passed

If the target date is in the past, the same subtraction gives a negative result: the number of days since. Seen from 13 September 2026, the result for 1 January 2026 is −255 days: 255 days, or 36 weeks and 3 days, have passed since New Year’s Day.

When does “today” change?

Today is taken as the start date in Türkiye time (UTC+3); the counter moves on one day at midnight in Türkiye. At the same moment the date can be different in another time zone. Hours are not counted; the result is in calendar days. For the Monday–Friday business days left, use the days between two dates.