Everyday Tools
Days Between Dates Calculator
Pick a start and end date to see the gap in days, weeks, months, and weekdays.
Calculation inputs
The end date can be before the start date — the result is shown as a negative span.
Results
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Complete the fields and select Calculate to show results here.
About this calculator
A days between dates calculator finds the exact span between two calendar dates in days, weeks, and months, along with a breakdown of weekdays and weekend days. It is handy for planning deadlines, counting time until an event, or checking someone's age in days.
How the calculation works
- Total days = end date − start date
- Whole months count calendar months, dropping a month when the end day is earlier than the start day
- Weekdays exclude Saturdays and Sundays across the span
Notes and assumptions
Dates are treated as whole calendar days, so time of day and time zones are ignored.
How it works in plain English
The calculator measures the raw number of days between a start and end date by comparing their positions on the calendar, which naturally accounts for different month lengths and leap years without needing any special adjustment. That day count is the most exact figure, since weeks and months are less precise units of time.
From the total days, the calculator derives a whole-weeks-plus-leftover-days figure and a decimal weeks value, along with a whole-months count. Whole months are found by comparing calendar months directly and adjusting by one if the end date's day of the month falls earlier than the start date's, since a month isn't finished until that day is reached again.
It also counts how many weekdays (Monday through Friday) and weekend days fall inside the span, which is useful for anything based on business days rather than calendar days, such as estimating a shipping or turnaround time.
The formula
- Total days = end date - start date
- Weeks = total days / 7
- Years (decimal) = total days / 365.25
Worked example
Checking the span from January 1, 2026 to December 31, 2026 gives 364 total days. That works out to 52 whole weeks with 0 leftover days (364 / 7 = 52 exactly), or 0.9973 years in decimal form. Whole months come out to 11, since the end date's day (31) falls after the 1st, so December isn't quite a complete additional month past November. Within that span, roughly 260 days are weekdays and the remainder are weekend days. Since 2026 is not a leap year, this 364-day span falls one day short of a full calendar year, which is why the decimal years figure lands just under 1.0 rather than exactly at it. A span running instead from January 1 through January 1 the following year would return exactly 365 days and 1.0 years.
Frequently asked questions
What happens if the end date is before the start date?
The calculator still computes the span, but the total days figure comes out negative, reflecting that the end date happened before the start date. This can be useful for checking how long ago a past date was relative to another.
Does the day count include both the start and end date?
The total days figure is the difference between the two dates, so it counts the number of days that have elapsed between them, not the number of calendar dates touched. Jan 1 to Jan 2 is 1 day apart, even though two distinct dates are involved.
Why don't days divided by 30 match the months figure shown?
The whole months figure counts actual calendar months, which vary between 28 and 31 days, rather than assuming a fixed 30-day month. This is more accurate for real calendar spans than a simple division of total days.
Do the results account for time zones?
No, both dates are treated as whole calendar days with no time-of-day or time zone component, since the tool is designed for day-level spans rather than precise timestamp differences. Someone comparing a start date at 11pm and an end date at 1am the next calendar day would still see the calculator count that as a difference of one calendar day, since it works entirely from date values rather than timestamps.
How are weekdays counted across the span?
Every Monday through Friday between the start and end date is counted as a weekday, and every Saturday and Sunday is counted separately as a weekend day, giving a simple business-day breakdown of the full span.