Counting Days: Inclusive or Exclusive?
Two honest answers to how many days until a date, and how to tell which one you are reading.
Two ways to count
Suppose today is Monday and an event is on Wednesday. Counting only the full days in between gives two days. Counting both endpoints gives three days. Neither answer is wrong — they answer different questions — but mixing them up causes missed deadlines.
What this site does
The days-until tools here count exclusively of today and inclusively of the target date: the number is how many midnights pass before the target day begins, plus the target day itself in plain language. Each tool states its rule on the page, so the number can be checked rather than trusted blindly.
A check you can do
If an event is tomorrow, a days-until answer of 1 should feel right. If it says 0 or 2 for tomorrow, the tool is counting differently — read its note, or count the midnights yourself.
More posts
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Daylight Saving and Time Zone Conversion
Why the gap between two cities changes through the year, and how converters handle DST gaps and repeats.
Leap Days, Birthdays and Age
What happens to a 29 February birthday in an ordinary year, and how age arithmetic handles it.
Month-End Overflow: Why January 31 Plus One Month Is Tricky
Adding months is not like adding days. Here is the clamping rule, and why it is the honest choice.
Why Timers Jump When a Tab Sleeps
Browsers slow down background tabs on purpose. Good timers do not count ticks — they subtract timestamps.