What this calculator does
A day counter tracks a running tally from a fixed starting point, the way a streak, a countdown or a "days since" tracker is usually read: the start date itself counts as Day 1, and the number climbs by one for every day that passes after it. Enter a start date and this calculator shows the current day number, updated to today by default.
This is a different question to asking for the gap between two dates. A day counter reports where you are in an ongoing count, such as day 47 of a habit or day 200 since an event, rather than just the size of the gap. Set the second date to anything other than today to check what day number a past or future date would have landed on.
The formula
The whole number of days between the start date and the date being checked is worked out first, then one is added, so the start date itself is Day 1 rather than Day 0. If the start date has not arrived yet, the calculator instead shows how many days remain until Day 1 begins.
| Term | Meaning |
|---|---|
| Day 1 | The start date itself, the first day of the count. |
| Full days elapsed | The whole day count between the two dates, not counting the start date, one less than the day number. |
The inputs explained
| Field | What to enter |
|---|---|
| Count from (start date) | The date the count begins on. This is Day 1. |
| Count to | The date to check the running count for. Defaults to today, for a live day counter. |
When to use it
Tracking a running streak or habit
A count that started on a fixed date and is meant to keep climbing, such as a habit, a challenge or a sobriety count, is exactly this kind of running tally, and the day number is usually the figure people actually want to see.
Working out what day number an anniversary or milestone falls on
A relationship, a business or a project sometimes gets referred to by its day number, such as "day 1000", and setting the date to check against finds exactly when that milestone lands.
Checking a business day counter style figure retrospectively
Moving the date being checked to a past date shows what the running count would have read on that day, useful for reconstructing a timeline after the fact.
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 grows as the start date moves further back
A range of start dates, each checked against today as the current running count.
| Start date | Day count | Weeks and days |
|---|---|---|
| today-7 | Day 8 | 1 week, 0 days |
| today-30 | Day 31 | 4 weeks, 2 days |
| today-90 | Day 91 | 12 weeks, 6 days |
| today-180 | Day 181 | 25 weeks, 5 days |
| today-365 | Day 366 | 52 weeks, 1 day |
| today-1000 | Day 1,001 | 142 weeks, 6 days |
Questions
Why is the day count one higher than the number of days between the two dates?
Because a day counter includes the start date itself as Day 1. Ninety days after the start date is Day 91, not Day 90, since the starting day is being counted too.
What happens if the start date is in the future?
The calculator recognises the count has not begun yet and instead shows how many days remain until Day 1, rather than showing a negative or misleading day number.
Can I use this as a business day counter, counting only weekdays?
This version counts every calendar day. For a count that skips weekends, the working days calculator gives the weekday-only total between two dates instead.
Is this the same as the days between dates calculator?
It is closely related but framed differently: this page reports a single running day number for a count already in progress, while the days between dates calculator reports the gap between two dates as its own figure, without treating either date as Day 1 of an ongoing count.
For the plain gap between two dates instead of a running count, see the days between dates calculator. To count only weekdays between two dates, use the working days calculator.