Date Calculator
Add or subtract days, weeks, months, or years from any date.
Date Calculator
Add or subtract days, weeks, months, or years from any date.
Date Difference Formula
ℹ️ Weeks = days ÷ 7 | Months ≈ days ÷ 30.44 | Years ≈ days ÷ 365.25
Disclaimer
Results provided by this calculator are for informational and educational purposes only. They are based on the values you enter and standard formulas, and should not be considered financial, medical, legal, or professional advice. Always consult a qualified professional before making important decisions based on these results. Roughtools makes no warranties regarding the accuracy or completeness of these calculations for your specific situation.
Frequently Asked Questions
Pro Tips
Business days vs calendar days matter for deadlines. A 30-day contract deadline is 30 calendar days, but a "30 business day" deadline is closer to 6 weeks.
Leap years (every 4 years, except century years not divisible by 400) add 1 day. Long-term date calculations that span February should account for this.
For countdown timers to important dates, include time zones — "Friday midnight" in New York is 3 hours different from California.
Age in years alone hides important milestones. "30 years, 6 months" is much more precise than "30 years old" for medical or legal calculations that need exact age.
When to Use This Calculator
Calculate exact days between today and a project deadline to plan work backwards.
Find exact age in days, weeks, or months for birthday milestones or official age verification.
Calculate days until a trip or visa expiry, or find the length of a journey between dates.
Verify contract end dates, notice periods, or lease expiry dates down to the exact day.
Count down days in a 30-day, 60-day, or 90-day fitness or habit challenge.
About the Date Calculator
This date calculator adds or subtracts any combination of days, weeks, months, and years from a starting date to find a past or future date. Enter your start date and the duration to add or subtract to instantly see the result date, the day of the week it falls on, and how many days separate the two dates. Built for project planners, HR professionals, legal deadline tracking, and anyone working with date arithmetic.
How to Use the Date Calculator
- 1
Enter the starting date using the date picker or type it in.
- 2
Choose the operation: add or subtract.
- 3
Enter the number of days, weeks, months, and/or years to add or subtract.
- 4
See the result date instantly, including the day of the week.
- 5
The total number of days between the two dates is also displayed.
Related Calculators
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Find what day of the week any date falls on — past, present, or future.
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Add and subtract hours, minutes, and seconds. Convert between time formats.
Time Duration Calculator
Calculate the exact duration between two times in hours, minutes, and seconds.
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