Date Calculator: Add, Subtract, and Find the Difference Between Dates
Our free Date Calculator makes time calculations simple. You can easily add or subtract days, weeks, months, and years from a starting date to find a future or past date. You can also use the days and months calculator feature to find the exact duration between two dates. This tool is perfect for project planning, event countdowns, age calculation, and tracking deadlines.
How to Use the Date Calculator
Our tool has two main functions: adding or subtracting time from a date, and finding the difference between two dates. Both are designed to be intuitive and fast.
Adding or Subtracting Time
- Select a Start Date: Use the date picker under the "Start Date" label to choose your initial date. Today's date is selected by default.
- Choose Operation: Click "Add" to calculate a future date or "Subtract" to find a past date.
- Enter the Amount: Type the number of days, weeks, months, or years you want to add or subtract.
- Select the Unit: Choose the time unit (Days, Weeks, Months, or Years) from the dropdown menu.
- Calculate: Click the "Calculate" button to see the resulting date and the day of the week it falls on.
Calculating the Difference Between Two Dates
- Switch Tabs: Click the "Date Difference" tab above the calculator.
- Enter Dates: Select the "From Date" (the earlier date) and the "To Date" (the later date) using the date pickers.
- Calculate Difference: Click the "Calculate Difference" button.
- View Results: The tool will display the total duration in a simple format (e.g., 1 year, 2 months) as well as a detailed breakdown of the total number of days, weeks, and months.
Common Uses for a Date Calculator
This tool is versatile and can be used for a wide range of personal and professional planning tasks.
Project Management
Quickly determine project deadlines and milestones. For example, if a project phase is estimated to take 90 days, you can add 90 days to the start date to find the exact completion date, instantly accounting for varying month lengths.
Event Planning
Count down to a wedding, vacation, or birthday. Use the Date Difference calculator to find out exactly how many months, weeks, and days are left until your big event. You can also use it to plan backwards from an event date to set reminders.
Personal Finance
Calculate loan durations, investment timelines, or determine maturity dates for financial products. For instance, find out the exact date 180 days from today for a billing cycle or a promotional offer's expiration.
Pregnancy & Due Dates
Track pregnancy milestones. Add 40 weeks to the date of the last menstrual period to estimate a due date, or calculate the date for important appointments that occur a specific number of weeks into the pregnancy.
Frequently Asked Questions
- How do I add days to a date?
- Select the "Add/Subtract Time" tab, choose your start date, select "Add", enter the number of days, and click Calculate. The result will show the new date.
- How do I calculate the difference between two dates?
- Use the "Date Difference" tab, enter your "From" and "To" dates, and click Calculate. You'll see the difference in days, weeks, months, and a detailed breakdown.
- Can I subtract time from a date?
- Yes! In the "Add/Subtract Time" tab, click the "Subtract" button, then enter how much time you want to subtract. This is useful for finding past dates or deadlines.
- What's the difference between adding 1 month and 30 days?
- Adding 1 month moves to the same day in the next month (e.g., Jan 15 + 1 month = Feb 15), regardless of month length. Adding 30 days always adds exactly 30 days. Months can be 28-31 days long.
- Does this account for leap years?
- Yes! The calculator automatically accounts for leap years when calculating dates and differences. February 29 is included in leap years.
- How can I find out the date 180 days from today?
- In the "Add/Subtract Time" tab, ensure the start date is set to today. Select "Add", enter 180 in the number field, choose "Days" as the unit, and click Calculate.
- What is the easiest way to calculate my age in days?
- Go to the "Date Difference" tab. Set the "From Date" to your birthdate and the "To Date" to today. Click calculate, and the "Total Days" in the result will show your exact age in days.
- Does this calculator include weekends and holidays?
- Yes, this calculator includes all calendar days (including weekends and public holidays). It does not calculate business days specifically.