Date Calculator
Calculate the number of days between two dates, or add and subtract days, weeks, months and years from any date. Useful for deadlines, travel planning, projects and subscriptions.
Days between dates
Find the exact number of calendar days between two dates.
0 days
Select two dates to calculate.
Add or subtract from date
Add or subtract days, weeks, months and years from a selected date.
Select date
Resulting date
Quick date calculation examples
Days between dates
Date difference calculations are useful when you need to count calendar days between two dates, such as time until a deadline, trip or event.
Adding days to a date
Add days, weeks, months or years when planning deadlines, renewals, follow-ups, projects or future reminders.
Subtracting from a date
Subtract time from a date to find earlier deadlines, preparation windows or when a period started.
Common date calculation mistakes
Forgetting whether the end date is included
Counting “between” two dates usually excludes the end date. If you need to count both dates, use the include end date option.
Mixing days and calendar months
One month is not always 30 days. Calendar months vary from 28 to 31 days.
Ignoring leap years
Leap years can affect date differences and future date calculations around February.
Free online date calculator
This date calculator helps you calculate days between two dates or add and subtract days, weeks, months and years from a date. It is useful for planning, scheduling and checking deadlines.
You can use it for travel planning, project timelines, subscriptions, follow-up dates, school schedules, work deadlines, legal periods, habit tracking and everyday calendar calculations.
When should you include the end date?
Include the end date when both the first and last day should count as part of the period. For example, if you are counting days of attendance, hotel nights or full calendar coverage, the answer may differ depending on whether the end date is included.
Date Calculator FAQ
How do I calculate days between two dates?
Select a start date and an end date. The calculator will show the number of calendar days between them.
What does include end date mean?
It means the end date is counted as part of the period. This adds one day to the result.
Can I add weeks and months to a date?
Yes. You can add or subtract days, weeks, months and years from any selected date.
Are months always counted as 30 days?
No. Months are treated as calendar months, so the result depends on the month length.
Does this calculator handle leap years?
Yes. The browser date logic handles leap years and normal calendar rules.
Is this date calculator free?
Yes. It is free and runs locally in your browser.