Days Between Dates Calculator

Days Between Two Dates

Start Date

End Date

Count only weekdays (Mon-Fri)

Add or Subtract Days from a Date

Starting Date

Days to Add/Subtract

How to Calculate Days Between Dates

Calculating the number of days between two dates is useful for project planning, calculating deadlines, tracking durations, and managing contracts.

Common Use Cases

Project deadlines: How many working days until delivery
Contract duration: Lease, subscription, or employment periods
Pregnancy tracking: Count weeks of gestation
Event planning: Days until wedding, vacation, or conference
Age calculation: Days since a milestone

How Are Weekdays Calculated?

When you select "weekdays only," the calculator counts Monday through Friday, excluding Saturday and Sunday. It does not account for public holidays, which vary by country and region.

How to Use the Days Between Dates Calculator

Enter the start date: Type or select the beginning date for your calculation. This can be any date in the past or future.
Enter the end date: Choose the second date to measure against. The calculator finds the exact span between these two points.
Review the results: The tool instantly shows the total number of days, weeks, months, and years between your two dates. It also breaks down the duration into combined units for easy interpretation.
Add or subtract days (optional): Use the date arithmetic feature to add or subtract a specific number of days from any date — perfect for calculating deadlines, due dates, or project milestones.

Understanding Date Duration Calculations

Calculating the number of days between two dates involves more than simple subtraction. While the core operation subtracts one date from another, the result must account for calendar complexities including leap years, varying month lengths, and the fact that months range from 28 to 31 days. The Gregorian calendar, used by most of the world, adds a leap day every four years except in century years not divisible by 400 — meaning the year 2000 was a leap year but 1900 was not.

When the calculator reports months or years between dates, it uses a convention where a "month" equals the transition from a given day in one month to the same day in the next month, and a "year" spans 12 such months. This means that the number of days in a month or year can vary. For precise day counts, the calculator always returns the total number of 24-hour periods, which is unambiguous and exact.

Date arithmetic is widely used in project management, contract law, HR administration, and financial calculations. Whether you need to calculate the number of working days for a project timeline, determine eligibility for benefits based on tenure, or compute interest accrual periods, having a reliable date calculator eliminates manual counting errors that can lead to costly mistakes.

Frequently Asked Questions

Does this account for leap years?

Yes. The calculator uses JavaScript's native Date object which correctly handles leap years. February 29 is included when applicable.

Does the weekdays count include holidays?

No. The weekday calculation counts Monday-Friday but does not exclude public holidays. For exact business days, you'd need a holiday calendar.

How accurate is the months calculation?

Months have varying lengths (28-31 days), so we use the average month length of 30.44 days for approximation. For exact results, use the days count.

Can I calculate days until a future event?

Yes. Enter today's date as the start date and your event date as the end date to see the countdown.

Can I calculate working days (business days) between dates?

The total day count includes weekends and holidays. To find working days, count only Monday through Friday. For precise business day calculations that exclude holidays, check the specific holiday calendar for your country or region.

Can I add or subtract days from a date?

Yes. Use the 'Add or Subtract Days from a Date' section: enter a start date and a positive or negative number of days, and the tool instantly shows the resulting date.