Breezy Tools

Date/Time Calculator

Calculate the difference between two dates or add/subtract time from a date.

Date Difference

0 years, 0 months, 0 days

0 total days · 0 total hours

Add / Subtract Days

How to Use Date/Time Calculator

  1. 1

    Choose a calculation mode

    Select either "Date Difference" to find the time between two dates, or "Add/Subtract" to calculate a new date by adding or subtracting a duration.

  2. 2

    Enter your dates

    Pick start and end dates using the date picker, or type them directly. Both modes support dates in the past and future.

  3. 3

    View the result

    The difference is shown in years, months, and days (and optionally hours and minutes). For add/subtract mode, the resulting date is displayed immediately.

Key Features

Two Calculation Modes

Find the exact difference between two dates, or add/subtract years, months, days, hours, and minutes from any date.

Granular Breakdown

Results show the difference in multiple units — years, months, days, hours, and minutes — for a complete picture.

Instant Calculation

Results update immediately as you change dates or durations, making it easy to experiment with different values.

Past & Future Dates

Works with any date — historical dates, today, or dates far in the future.

Common Use Cases

  • Project Deadlines

    Calculate how many days remain until a project deadline, or find the end date when given a duration in weeks or months.

  • Age Calculation

    Enter a birth date and today's date to find an exact age in years, months, and days.

  • Contract & Warranty Periods

    Determine when a 90-day warranty expires or how much time is left on a 2-year contract.

  • Event Planning

    Count down to a wedding, vacation, or product launch by calculating the number of days from today to the event date.

Frequently Asked Questions

How does the tool handle leap years?▾

The calculator correctly accounts for leap years. February 29 is included in calculations when the date range spans a leap year, so durations are always accurate.

Can I calculate the difference in business days?▾

Currently the tool calculates calendar days. Business day calculations (excluding weekends and holidays) are not yet supported.

What date formats are supported?▾

The tool uses your browser's native date picker, which displays dates in your locale's format. Internally, all dates are processed as standard date values regardless of display format.

Is there a limit on how far apart dates can be?▾

No practical limit. The tool can calculate differences between dates spanning centuries — useful for historical research or far-future planning.