Date Calculator
Days between two dates, or add / subtract days from any date.
Quick:
About This Date Calculator
The Days Between mode calculates the number of calendar days between two dates, plus the result expressed in weeks and months. It also shows the day of the week for each date, which is useful for scheduling. All calculations account for leap years automatically.
The Add / Subtract mode finds what date falls a certain number of days in the future or past — useful for calculating deadlines, expiry dates, notice periods, and project milestones. Click any result card to copy the value. Everything runs locally in your browser.
How to Use
- Choose Days Between to count days between two dates, or Add / Subtract to calculate a future or past date.
- Enter your dates — results appear instantly.
- Use the Quick buttons to set the end date to +7, +30, +90 days or +1 year from today.
- Click any result card to copy the value to your clipboard.
Frequently Asked Questions
The default count is exclusive of the start date and inclusive of the end date — this is the standard "number of days between" interpretation. For example, from Monday to Friday is 4 days. If you need to count both the start and end date (inclusive on both ends), simply add 1 to the result.
Months are displayed as a decimal figure based on dividing the day count by 30.4375 (the average days per month in a year). This gives an approximate month count — for example, 92 days ≈ 3.02 months. For exact month counts (e.g. "exactly 3 months"), use the months field which counts whole calendar months between the two dates.
No. All calculations run entirely in your browser. No data is sent to any server.