Date Calculator - Date Calculator Add Subtract Days
Use our free date calculator to add or subtract days from any date, or calculate the difference between two dates. Our date calculator add subtract days helps you find future dates, past dates, and time between dates.
Calculate date differences, add or subtract days, and perform various date operations
Date Calculator
How to Use This Calculator
- Select the type of date calculation you need
- Enter the start date
- Enter the end date (for difference) or number of days (for add/subtract)
- Click calculate to see the results
Quick Examples
Date Calculation Results
Enter dates to perform calculations
Date Calculator Features
Date Difference
Calculate the exact number of days, weeks, months, and years between two dates.
Add Days
Add a specific number of days to any date to find the future date.
Subtract Days
Subtract a specific number of days from any date to find the past date.
Common Use Cases
Personal Use
- • Calculate age in days, months, and years
- • Find days until birthday or anniversary
- • Calculate vacation duration
- • Track project timelines
- • Countdown to important events
Business Use
- • Calculate payment due dates
- • Track project deadlines
- • Calculate interest periods
- • Determine warranty periods
- • Plan delivery schedules
About the Date Calculator
Our free date calculator finds the difference between two dates in days, weeks, months, and years, or adds and subtracts days from a date. Use it for project deadlines, age calculation, payment terms, and countdowns. Select start and end dates for a difference, or one date plus days to add or subtract. Results show calendar days and approximate weeks and months. For working days only, use our business day calculator. For age in years and months, try our age calculator.
Frequently Asked Questions About Date Calculator
How do I calculate days between two dates?
Enter the start and end dates and choose "Date Difference". The calculator shows total days, and approximate weeks and months.
Can I add or subtract days from a date?
Yes. Choose "Add Days" or "Subtract Days", enter the start date and number of days, and get the resulting date.
Does this include leap years?
Yes. The calculator uses the actual calendar, so leap years are included in the day count and in add/subtract operations.
How the Date calculator works
This free date calculator runs entirely in your browser using standard mathematical formulas. Enter your figures, tap Calculate, and results update instantly — no signup required.
Figures are estimates for general information. Always verify important decisions with a qualified professional where relevant.
- Input your values using the fields above (numeric keypad on mobile).
- Results use precise floating-point arithmetic rounded for display.
- Refresh or change inputs and recalculate anytime.
Worked example
- Choose typical values for a common date scenario.
- Enter those values in the calculator fields above.
- Tap Calculate and compare the on-screen result with the expected formula outcome.
- Adjust one input at a time to see how the result changes.