Date Calculator Online — Add & Subtract Days, Weeks, Months from Any Date

How to Use Date Calculator

1. Select a starting date: Enter or pick the starting date using the date picker.
2. Choose the operation: Select whether to add or subtract time from the starting date.
3. Enter the duration: Type the number of days, weeks, months, or years to add or subtract.
4. View the result: The resulting date is displayed instantly.

Features

• Add or subtract days, weeks, months, and years from any date
• Calculate the difference in days between two dates
• Accounts for leap years and varying month lengths
• Runs entirely in your browser — no server calls
• Free with no account required
• Useful for deadlines, project planning, and contract dates

Common Use Cases

Date calculation is essential for project managers tracking deadlines, HR professionals calculating notice periods and probation end dates, lawyers computing contract terms, and individuals planning trips or anniversaries.

Frequently Asked Questions

Does the calculator account for leap years?

Yes. All calculations correctly account for leap years and the different lengths of calendar months.

Can I calculate how many days are between two dates?

Yes. Enter both a start date and an end date to get the exact number of days between them.

What is the furthest date I can calculate to?

The tool supports any date within the JavaScript Date range, which covers dates from roughly year 100 to year 275,000.

Can I add business days only (excluding weekends)?

The standard calculator adds calendar days. A business-day mode may be available as a separate option in the tool.

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