This free days between dates calculator measures the span between two calendar dates. You get total days, a years/months/days breakdown, weeks, and business days that skip weekends. Use Days until mode when you only care how long it is from today to a future date. It is built for US project timelines, leave plans, and countdown checks.
How to use this days between dates tool
- Pick a modeDays between dates or days until a date.
- Set the datesChoose start and end, or a target date.
- Compare rangesUse a full range for start and end.
- Read the countSee calendar days, Y/M/D, and business days.
The formula behind it
Calendar days are the absolute difference between the two local dates. The years/months/days breakdown uses completed calendar units from the earlier date to the later date. Business days count Mondays through Fridays, inclusive of both ends, with no holiday calendar applied.
Example: From Monday, January 1, 2024 to Wednesday, January 31, 2024 there are 30 calendar days and 23 business days.
Sample date spans
| Date range | Result |
|---|---|
| Jan 1 to Jan 31 (same year) | 30 calendar days |
| Mon–Fri same week | 4 calendar days, 5 business days if both ends count |
| Friday to next Monday | 3 calendar days, 2 business days |
| Same start and end | 0 calendar days |
| One full non-leap year | 365 calendar days |
| One full leap year | 366 calendar days |
US planning notes for date math
US forms usually expect month/day/year display, but this tool uses a standard date picker so the underlying value stays unambiguous.
Business days here mean weekdays only. Federal holidays, company blackout days, and school breaks are not removed.
Leave policies may count inclusive or exclusive end dates. Confirm whether your workplace includes the start day, the end day, or both.
For age-style spans, years/months/days is easier to read than raw day totals. For deadlines, total days and business days are usually clearer.
Frequently asked questions
How many days are between two dates?
Count the calendar day difference between the earlier and later dates. The same day is 0 days apart in this tool.
How do I calculate business days between two dates?
Count Monday through Friday dates from the start date through the end date. This tool does that automatically and skips weekends only.
How many days until a future date?
Use Days until mode, choose the target date, and read the calendar day count from today.
Does the days between dates calculator include the end date?
Calendar days use the difference between dates, so the same day is zero. Business days count both ends when they fall on weekdays.
Are US holidays excluded from business days?
No. Only Saturdays and Sundays are excluded. Holiday calendars vary by employer and jurisdiction.
More free calculators
Related: date difference calculator, age calculator, and the Calculators hub.
For timekeeping standards context, see NIST - Time and Frequency Division.