The Date Calculator finds the difference between two dates or adds/subtracts days, weeks, months, and years from a date. It's useful for calculating deadlines, project timelines, contract durations, event countdowns, and age-related computations.
How the Formula Works
Calculates the exact difference between two dates accounting for varying month lengths (28–31 days) and leap years (every 4 years, except centuries not divisible by 400).
How to Use This Calculator
Enter a start date and end date, or
Enter a start date and number of days/weeks/months to add or subtract
View the result with breakdown in multiple units
Tips & Best Practices
Business days exclude weekends (Saturday and Sunday) and usually holidays
A 'fortnight' is exactly 14 days or 2 weeks
Months have different lengths — always verify exact day counts for precise calculations
Important Limitations
Business day calculations may not account for all public holidays in your region
Does not account for timezone changes or daylight saving time transitions