Date Calculator
Calculate the difference between two dates, add or subtract time periods (days, weeks, months, years), and perform date arithmetic. This tool helps you calculate durations, deadlines, and time intervals between dates.
When to use this tool
You need to calculate deadlines or intervals between dates.
You want to add or subtract time from a given date quickly.
Examples
Add 30 days
Input
Start: 2025-01-01 Add: 30 days
Output
2025-01-31
Month boundaries affect results for longer ranges.
Developer use cases
Compute trial expiration dates.
Calculate project timelines or delivery windows.
Common mistakes to avoid
Mixing inclusive vs exclusive date ranges.
Assuming every month has the same number of days.
Format and behavior notes
Calculations respect calendar month lengths.
Use clear start/end dates to avoid off-by-one errors.
Related guides
Related Tools
Frequently Asked Questions
How do I calculate date differences?
Enter two dates and the tool will calculate the difference in days, weeks, months, and years between them.
Can I add or subtract time from a date?
Yes, enter a date and specify how many days, weeks, months, or years to add or subtract. The result will be calculated instantly.
What date formats are supported?
The tool supports various date formats including MM/DD/YYYY, DD/MM/YYYY, YYYY-MM-DD, and more.