Date Calculator
Calculate date differences, add or subtract time periods, and find what day of the week any date falls on — all with business day support.
How to Use the Date Calculator
Select the calculation type you need, enter your dates, and see instant results. Use the "Today" button to quickly fill in today's date.
- Choose a mode: Date Difference (days between two dates), Add/Subtract (find a future or past date), or What Day (find the day of the week).
- Enter the dates: Click the date input to open a calendar picker, or type the date directly in YYYY-MM-DD format.
- Enable business days if you want to exclude weekends from the calculation (Saturday and Sunday).
- Read the result on the right (or below on mobile). Additional details like weeks, months, and day of week are shown.
What are Business Days?
Business days (also called working days or weekdays) are Monday through Friday, excluding Saturday and Sunday. Many businesses, government offices, and financial institutions operate on business day schedules.
When you enable the "Business days only" option, the calculator will skip all Saturdays and Sundays. This is useful for calculating project deadlines, delivery dates, or payment terms that only count working days.
Note: This calculator does not account for public holidays, which vary by country and region. For calculations that include holidays, use a specialized business day calculator with holiday support.
Common Date Calculation Scenarios
| Scenario | Mode to Use | Example |
|---|---|---|
| How many days until vacation? | Date Difference | Today to June 15 = 120 days |
| When is the invoice due (net 30)? | Add/Subtract | Today + 30 days = March 15 |
| What day was my birthday in 1990? | What Day | April 10, 1990 = Tuesday |
| Project deadline in 20 business days | Add/Subtract (business days) | Today + 20 business days = March 20 |
| Age in days | Date Difference | Birthdate to today = 10,950 days (30 years) |