CodeKitHubWhat Is This Tool?
A days-until calculator answers the single question behind countless countdowns: how many full days separate today from a chosen date? It works in both directions — a future date gives you a countdown ('123 days left'), a past date gives you a count-up ('87 days ago'). The math is simple date subtraction, but doing it by hand across month boundaries and leap years is exactly the kind of thing people get wrong by one or two days.
The counter uses whole calendar days: today is not counted, the target date is. That matches how people naturally count — if an exam is tomorrow, 'one day left' feels right. Because the calculation walks the real calendar, months of different lengths and February 29 in leap years are handled automatically.
Why Use It?
- Works both ways: countdown to a future date and days elapsed since a past one.
- Breaks the result into weeks + days and an approximate number of months.
- Counts the weekend days (Saturdays and Sundays) inside the span — handy for planning.
- One-click buttons for common dates: New Year, Valentine's Day, Halloween, Christmas, New Year's Eve.
- Free and instant, with nothing uploaded — the calculation runs entirely in your browser.
How to Use
- Pick a date with the date field, or hit one of the quick buttons for common dates.
- Press the calculate button.
- Read the day count — the tool automatically shows 'days until' for future dates and 'days since' for past ones.
- Check the breakdown line for weeks, months and weekend days in between.
Example
Input
Today is July 28 and the selected date is December 25Output
150 days — 21 weeks and 3 days, about 4.9 months, 42 weekend days in betweenJuly 28 itself is not counted; December 25 is. The weekend count includes every Saturday and Sunday between the two dates.
Handy day-count reference
| Span | Days | Weeks |
|---|---|---|
| 1 week | 7 | 1 |
| 30 days | 30 | 4 weeks 2 days |
| 90 days | 90 | 12 weeks 6 days |
| Half a year | 182–183 | 26 weeks |
| 1 year (common) | 365 | 52 weeks 1 day |
| 1 year (leap) | 366 | 52 weeks 2 days |
Related date and time tools
For adding or subtracting days from a date — for example 'what date is 90 days from today?' — the Date Calculator is the right tool, and it also splits any interval into exact years, months and days.
The Age Calculator turns a birth date into an exact age, and the Timestamp Converter translates between human dates and Unix timestamps for developers.
→ Date Calculator · Age Calculator · Timestamp Converter · Sunrise and Sunset Calculator
Frequently Asked Questions
How do you calculate the number of days between two dates?
Convert both dates to a day number on a continuous calendar and subtract. In practice, calendar software counts the days by walking the real calendar, which automatically accounts for 30- and 31-day months, February, and leap years. This tool does the same, so a span crossing February 29 comes out correct without any manual adjustment.
Does today count as one of the days?
No. The counter uses the common convention: today is day zero and the target date is included. If today is Monday and the event is Wednesday, the answer is 2 days. If you need an inclusive count where both endpoints count — some contract and medication schedules work that way — simply add 1 to the result.
How do leap years affect the count?
A leap year inserts February 29, making that year 366 days long. If your span crosses a February 29, it is simply one day longer than the same span in a common year. The calculator walks the actual calendar, so leap days are included automatically — nothing to correct for.
Why is the month figure approximate?
Months have different lengths (28 to 31 days), so a fixed number of days doesn't map to an exact number of months. The tool divides by the average month length of 30.44 days to give a useful approximation. For a precise years-months-days split between two dates, use the Date Calculator instead.
Can I also count how many days have passed since a date?
Yes — just pick a past date. The tool detects the direction automatically and switches from 'days until' to 'days since'. This is handy for anniversaries, tracking a habit streak, or knowing how old an event, invoice or document is in days.
Is my data stored anywhere?
No. The calculation runs in your browser with JavaScript; the dates you pick are never sent to a server, stored or logged.