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Date & Timedates

Days Until Date Calculator

Days until a date, with the working days separated out. Counting at UTC midnight means a range crossing a daylight saving change is still a whole number of days.

Also called: countdown calculator, days between dates.

Days
358

358 days, which is 51 weeks and 1 days. 2026-12-25 falls on a Friday. There are 256 working days and 102 weekend days in between.

In weeks and days
51 weeks and 1 days
Working days
256
Weekend days
102
The target day
Friday
Hours
8,592
Approximate months
11.76
How this is calculated
Method and background

How this is calculated

The difference in milliseconds divided by a day. Doing that in a local time zone is where this goes wrong: a range crossing a daylight saving boundary is 23 or 25 hours on one of its days, so the division returns a fraction and rounds unpredictably. Fixing both ends at UTC midnight makes the answer exact. Working days count weekdays only, since holidays vary by country and are not known here.

days = the difference in UTC milliseconds over a day, which is exact because no daylight saving applies
t
Timestamps at UTC midnight

Worked examples

Each of these is asserted on every build. If a change to the engine ever moved one of these answers, the build would fail before the page could print it.

new year to christmas

From
2026-01-01
Until
2026-12-25

Days358

Counted independently across a non-leap year

Open this example

the same date is zero days

From
2026-01-01
Until
2026-01-01

Days0

boundary

Open this example

Method and limits

What it assumes

  • Both dates at UTC midnight, and the count excludes the start date.

What it deliberately does not model

  • Public holidays are not deducted from the working-day count.

Formula version 1.0.0 · definition 1.0.0 · United States · Report a problem with this calculator

Frequently asked questions

Does the count include the start or end date?
Neither end is double counted: it is the number of days between them, so 1 January to 2 January is one day.