Date Calculator: Find Days Between Dates or Add Days

Need to know how many days until a deadline? Or what date is 90 days from today? Our free Date Calculator handles both calculations instantly with two modes: Days Between and Add/Subtract Days.

How to Use the Date Calculator

Days Between Mode

1. Select a start date and end date
2. See the difference in days, weeks, months, and years
3. Results update automatically as you change dates

Add/Subtract Days Mode

1. Select a start date
2. Enter the number of days to add (use negative numbers to subtract)
3. See the resulting date and day of the week
4. Use quick buttons for common intervals (+7, +30, +90, +365)

Common Use Cases

• Project planning: Calculate timeline durations and deadline dates
• Contract management: Find expiration dates from start dates
• Travel planning: Count days until departure or trip duration
• Pregnancy tracking: Calculate due dates and trimester milestones
• Legal deadlines: Determine filing dates based on regulatory periods
• Event planning: Count down to weddings, conferences, or launches

Tips

• The calculator accounts for varying month lengths and leap years
• Use negative days in Add/Subtract mode to find past dates
• Days Between always returns a positive number regardless of date order

Frequently Asked Questions

Does it account for leap years? Yes. The calculation uses JavaScript’s native Date object, which correctly handles leap years.

Is the end date included in the count? The count represents the difference between the two dates. February 1 to February 3 = 2 days.

Can I calculate business days only? This tool calculates calendar days. For business days, subtract weekends manually (roughly multiply by 5/7).

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Try our free Date Calculator to find dates and durations instantly.