What this calculator does
A days calculator counts the number of days between two dates. Enter a first and second date and the result comes back both ways: the number of nights between them, and the inclusive count that also counts the start and end date themselves, since the two questions genuinely have different answers.
The gap between "how many days between" and "how many days including both dates" is exactly one day, and it is the detail people most often get wrong doing the sum by hand. Booking a hotel for three nights and a trip lasting three days are not quite the same count, and this calculator shows both figures side by side.
The formula
The exclusive count is the number of whole days between the two dates, the same as the number of nights if you were staying somewhere for that span. The inclusive count adds one, so that both the first and last date are counted as full days.
| Term | Meaning |
|---|---|
| First date | The earlier reference point for the count. |
| Second date | The later reference point for the count. |
| Exclusive count | Days between the two dates, not counting either end date itself. |
| Inclusive count | Days between the two dates, counting both the first and last date. |
The inputs explained
| Field | What to enter |
|---|---|
| First date | The first date, defaulting to today. |
| Second date | The second date to count to. |
| Counting | Whether to show the exclusive or inclusive count as the headline figure. |
When to use it
How many days until an event
Counting forward from today to a future date is the most common form of the question, and works the same whether the target is a deadline, a trip or a booking.
Checking the length of a stay or booking
A hotel or rental booking is usually priced by nights, which is the exclusive count, while a trip itinerary is often described inclusively, covering both the arrival and departure day.
Confirming a day count that feeds into another calculation
Payroll, interest and rent proration sometimes depend on whether a period is counted inclusively or exclusively, and getting that one day wrong changes the result.
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How the day count from today grows as the second date moves further out
The exclusive and inclusive day counts from today to a series of later dates.
| Second date | Days | Exclusive count (nights between) | Inclusive count (both dates counted) |
|---|---|---|---|
| today+7 | 7 | 7 | 8 |
| today+30 | 30 | 30 | 31 |
| today+60 | 60 | 60 | 61 |
| today+90 | 90 | 90 | 91 |
| today+180 | 180 | 180 | 181 |
| today+365 | 365 | 365 | 366 |
Questions
How many days between two dates, not counting either one?
That is the exclusive count: the number of full days that separate the two dates, equivalent to the number of nights if the span were a stay somewhere.
How many days including both the start and end date?
That is the inclusive count, which is always one higher than the exclusive count, since it additionally counts the first date as a full day.
Which count should I use for a trip or booking?
Hotel and rental bookings are typically priced by nights, which matches the exclusive count. A day-by-day itinerary that lists every calendar day of the trip, including departure day, matches the inclusive count instead.
Does the order I enter the two dates in matter?
No. The day count is worked out as a positive number regardless of which date is entered first; the calculator also states which of the two dates is later.
For a fuller breakdown that also shows years, months and business days, see the time between dates calculator. To count only weekdays between two dates, use the working days calculator.