Date Difference Calculator: Find Days, Weeks & Months Between Dates

How many days until your vacation? How long ago did you start your job? When is 90 business days from today? A date difference calculator answers these questions instantly.

Use our free date difference calculator to find days, weeks, months, and years between any two dates.

What Can You Do With a Date Calculator?

• Countdown to events — weddings, holidays, product launches
• Calculate age — days since birth, anniversaries, or milestones
• Project planning — find deadlines 30/60/90 days from now
• Contract durations — verify lease lengths or warranty periods
• Business days — calculate working days excluding weekends

How to Use the Date Difference Calculator

1. Pick your start date from the calendar
2. Select your end date
3. Instantly see results in days, weeks, months, and years
4. Toggle business day mode for working-day calculations
5. Use date addition/subtraction to find a date ± N days

Why Choose Our Date Calculator

• Multiple units — not just days, but weeks, months, and years too
• Business day mode — exclude weekends for work planning
• Date arithmetic — add or subtract days from any date
• Calendar picker — intuitive date selection on desktop and mobile
• All local — no server requests, instant results

Common Date Calculation Scenarios

Use Case	Calculation
90-day probation period	Start date + 90 business days
Invoice due date	Invoice date + 30 calendar days
Days until retirement	Retirement date - today
Project timeline	End date - start date = duration
Age in days	Today - birth date

Pro Tips

1. For deadlines, always check whether “days” means calendar or business days — mixing them up can cause missed deadlines
2. Account for holidays — our business day mode excludes weekends, but you may need to manually account for public holidays
3. Date formats — input dates in your preferred format and let the calculator handle the conversion

Related Tools:

• Age Calculator
• Unix Timestamp Converter
• Text Analyzer