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Date Calculator - Days Between Dates
Free date calculator to find days between dates, add or subtract days/weeks/months, and calculate business days. Easy date math.
Date Calculator
Calculate differences and perform operations with dates
Result
Enter your values to see results
and click the "Calculate" button
What is Date Calculation?
Date calculation helps you find the difference between two dates or add/subtract time from a date. Useful for project deadlines, contract durations, pregnancy tracking, countdown to events, and calculating business days. This tool supports 5 different date calculation modes.
How to Use This Calculator
- Select the type of calculation
- Enter the start date
- Enter the end date or amount to add/subtract
- Click Calculate to see the result
Date Calculation
Days = End Date - Start Date
For business days, subtract weekends (Saturdays and Sundays). Holidays are not automatically excluded.
Frequently Asked Questions
How do I calculate days between two dates?
Subtract the earlier date from the later date. If today is January 3 and the end date is February 15: February 15 - January 3 = 43 days. Add 1 if you want to include the end date.
How are business days calculated?
Count total days and subtract Saturdays and Sundays. A week has 5 business days. Public holidays must be subtracted manually.
Is adding 30 days the same as adding 1 month?
No! Months vary from 28-31 days. January 1 + 1 month = February 1. But January 1 + 30 days = January 31. Different results!
What is a leap year?
A leap year has 366 days (February 29). A year is a leap year if divisible by 4, except years divisible by 100 (unless also divisible by 400). 2024, 2028 are leap years. 2100 is not.
How many business days in a year?
52 weeks × 5 days = 260 days. After subtracting public holidays, approximately 250-252 business days depending on how holidays fall.
How do I find what day of the week a date is?
Use this calculator - enter any date and it will tell you the day of the week. For example, January 1, 2026 is a Thursday.
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