Calculate the exact number of days, weeks, and months between any two dates — instantly and accurately.
The Days Between Dates Calculator tells you exactly how many days, weeks, and months separate any two dates. This is one of the most practical utility tools available — it's used for project planning, countdown timers, legal and contractual deadlines, age calculations, anniversary planning, and much more.
Common Uses
- Project planning: How many days remain until a project deadline? How many working days between kickoff and delivery?
- Contracts and legal: Loan agreements, lease terms, and service contracts often specify periods in days. "90 days from signing" — what is the exact date?
- Age and anniversaries: How many days since a specific life event? How many days until an anniversary or birthday?
- Countdowns: Days until an exam, a trip, a wedding, or a product launch.
- Financial calculations: Interest calculations on loans, deposits, or bonds often require the exact number of days between dates.
- Due dates: Pregnancy is approximately 280 days from the last menstrual period — how many days remain?
How to Enter Dates
Enter the start and end dates using year, month (1-12), and day fields. The calculator works with any two dates in either order — it always returns the absolute difference, so you don't need to worry about which date is "first."
Accounting for Leap Years
This calculator accounts for leap years automatically. February has 28 days in most years but 29 in leap years (every 4 years, with some exceptions). The calculation is based on exact calendar dates rather than a fixed 365-day year, so the result is always accurate.
1. Enter Start Date: Type the start year, month (1-12), and day.
2. Enter End Date: Type the end year, month, and day.
3. View Results: The calculator shows the exact number of days between the two dates, plus equivalent weeks, months (approximate), and years (approximate).
The calculation uses JavaScript's Date object for exact calendar-aware date arithmetic:
Total Days = |Date2 − Date1| / (1000 × 60 × 60 × 24)
(Absolute value of difference in milliseconds, converted to days)
Weeks = floor(Total Days / 7)
Months ≈ round(Total Days / 30.44) (30.44 = average days per month)
Years ≈ Total Days / 365.25 (365.25 accounts for leap years)
This approach automatically handles leap years, month-length variations, and daylight saving time changes.
Example 1: Jan 1, 2025 to Dec 31, 2025 → 364 days (not 365, because the start day counts as day 0). Weeks = 52.
Example 2: Jan 1, 2020 to Jan 1, 2030 → 3,653 days (spans 2 leap years: 2020 and 2024 → adds 2 extra days over 10 years × 365 = 3,650). ≈ 10.00 years.
Example 3: March 15, 2000 to March 15, 2026 → 9,497 days (26 years, accounting for all leap years between 2000 and 2024).