Date Calculator
Free online date calculator to find the exact difference between two dates or add and subtract days, weeks, months, and years from any date. Instant results with detailed breakdowns.
Start Date
From when to start counting
End Date
Until when to count
How to Use Date Calculator
- 1 Choose a mode: "Date Difference" to find time between two dates, or "Add / Subtract" to shift a date
- 2 For Date Difference: select a start and end date using the date pickers
- 3 View the detailed result showing years, months, days, total days, weeks, weekdays, and weekends
- 4 For Add/Subtract: enter a starting date and the amount of days, weeks, months, or years to add or subtract
- 5 The calculated result date appears instantly in the preview panel
- 6 All calculations run locally in your browser — nothing is sent to any server
What You Get
Online date calculator with two modes: Date Difference (find exact time between two dates with breakdown in years, months, days, weeks, weekdays, weekends) and Add/Subtract (add or subtract days, weeks, months, or years from any date). Supports dates from year 0001 to 9999. Handles leap years correctly. Works entirely in the browser.
Input: From January 1, 2024 to February 9, 2026
Output: 2 years, 1 month, 9 days (770 total days, 110 weeks, 550 weekdays, 220 weekend days)
Input: Today + 90 days
Output: Exact future date with day-of-week
Input: December 25, 2025 minus 6 months
Output: June 25, 2025 (Wednesday)
How do I calculate the number of days between two dates?
Select the "Date Difference" mode, then pick your start date and end date. The calculator instantly shows the exact difference in years, months, days, total days, weeks, weekdays, and weekend days. The result updates in real time as you change either date.
Does this calculator count the start date or end date?
This calculator counts the days between the two dates, not including the start date but including the end date. For example, from January 1 to January 3 is 2 days. This matches how most people naturally count days (e.g., "2 days until Friday" means today is Wednesday).
How do I add days to a date?
Switch to the "Add / Subtract" mode. Enter your starting date, select "Add" or "Subtract", choose the unit (days, weeks, months, or years), and enter the amount. The result date appears instantly. For example, adding 90 days to today shows the exact date 90 days from now.
Does this calculator handle leap years?
Yes. The calculator correctly handles leap years using the standard Gregorian calendar rules: a year is a leap year if divisible by 4, except for century years, which must be divisible by 400. So 2024 is a leap year (divisible by 4), 1900 was not (century not divisible by 400), and 2000 was (century divisible by 400).
What is the difference between weekdays and business days?
Weekdays are Monday through Friday (5 days per week), excluding Saturday and Sunday. Business days typically also exclude public holidays, which vary by country. This calculator counts weekdays (Mon-Fri) in the Date Difference mode. For business day calculations that account for holidays, use our Business Days Calculator.
Can I calculate months and years between dates?
Yes. The Date Difference mode breaks down the result into years, months, and remaining days. For example, the difference between March 15, 2023 and July 20, 2025 is 2 years, 4 months, and 5 days. It also shows the total in days, weeks, and weekdays for a complete picture.
How far back or forward can I calculate?
The calculator supports dates from January 1, 0001 to December 31, 9999, covering the entire range of the Gregorian calendar. This is more than sufficient for any practical date calculation, whether you are calculating historical dates or planning far into the future.
Is this date calculator free?
Yes, this calculator is 100% free with no account required. All calculations run entirely in your browser — no data is sent to any server. There are no ads, no usage limits, and no premium features locked behind a paywall.
All calculations run in your browser. Nothing is sent to any server.