Add or subtract time, or find the duration between two dates.
Choose a mode, set your dates, and get precise results — including business days and time zone awareness. Everything runs on your device.
Pick any date on the calendar.
Edit any unit — the result updates automatically.
Four steps, a precise date.
No manual required — here's the entire flow.
Pick a mode
Choose Add / Subtract to shift a date, or Date Difference to measure the gap between two dates.
Set your dates
Use the calendar pickers to select a start date and, for differences, an end date.
Adjust options
Toggle business days, include the end date, or fine‑tune the amount with years, months, weeks and days.
Read the result
The tool shows a clean, copy‑ready summary. Use the copy or download buttons to save it.
Built for accuracy, not guesswork.
The details that make date math reliable — without ever leaving your browser.
Runs on your device
All calculations happen locally in JavaScript. Your dates never leave your device.
Business-day aware
Count only working days for project planning, delivery estimates, or payroll cycles.
Precise breakdowns
Get a detailed breakdown of the duration in every unit — ready to copy or download.
Questions people actually ask.
The short answers — with the long ones one tap away.
How do I calculate the number of days between two dates?+
Open the Date Difference tab, enter your start and end dates, and the tool instantly shows the total days, weeks, months, and years between them. You can also include or exclude the end date and count only business days.
How do I add or subtract days from a date?+
Use the Add / Subtract tab, pick your start date, choose whether to add or subtract, and enter the number of days, weeks, months or years. The result updates live.
Does this date calculator count business days?+
Yes. Toggle the Business days option in the Date Difference tab to exclude Saturdays and Sundays from the count. This is useful for project planning and delivery estimates.
Is the date calculator time zone aware?+
The tool uses your browser's local time zone for the current date and for all calculations. The date values themselves are time‑zone neutral, so results stay consistent across regions.
Can I include the end date in the duration?+
Yes. Toggle the Include end date option to count the end date as part of the duration. By default the end date is excluded, which is the standard convention for most date math.
Is my data uploaded to a server?+
No. All date calculations run locally in your browser using JavaScript. Your dates never leave your device.
Is this date calculator free?+
Yes, it's completely free with no account, no sign-up, and no limit on how many times you use it.
Can I copy or download the results?+
Yes. Use the copy button to copy the result summary, or download the full breakdown as a .txt file for your records.