Calculate the days between dates, count business days, or find any date after adding or subtracting days, weeks, and months. Free date difference calculator — instant results.
📅
Date Calculator
Date difference & date arithmetic
Duration
—
Total Days
—
Total Weeks
—
Weekdays
—
Weekends
—
Result Date
—
From
—
To
—
Days Changed
—
Day of Week
—
How to Use the Date Difference Calculator
This date calculator has two modes: Date Difference, which calculates how many calendar days, business days, weekdays, and weeks fall between any two dates; and Add/Subtract Days, which finds the exact date after adding or subtracting any number of years, months, weeks, or days from a starting date. Both modes work for any past or future dates — from calculating how many days until a vacation to figuring out what date falls 120 business days from contract signing. Leap years are handled automatically, so February 29 is correctly included when applicable.
US workers and project managers use the business days calculator constantly: a contract with "30 business days to close" means approximately six calendar weeks, not 30 calendar days. HR departments track payroll cycle dates, benefits waiting periods, and FMLA leave durations in business days. The IRS uses calendar days for tax deadlines — your return is due 3 months and 15 days after the close of your fiscal year, and the day-by-day count matters for late filing penalties. This calculator makes all of these computations instant, removing the manual counting that leads to mistakes.
📅
Days Between Dates
Calculate exact day counts between any two dates — birthdays, anniversaries, project deadlines, or retirement dates. Results include total days, weeks, weekdays, and weekend days all at once.
💼
Business Days Calculator
A typical US work year contains about 260 business days. Contract terms, court deadlines, and banking transactions often specify business days — this mode excludes weekends for accurate professional calculations.
➕
Add / Subtract Days
Find out what date falls 45 days from today, or what day of the week January 1, 2027 falls on. Useful for calculating due dates, lease expirations, warranty end dates, and subscription renewals.
🗓️
Practical US Examples
IRS tax deadlines, FMLA leave tracking, contractor milestone dates, visa expiration countdowns, mortgage rate lock periods — this calculator handles them all by simply entering your start and end dates.
Frequently Asked Questions
Select Date Difference mode, enter start and end dates, click Calculate. The calculator shows total days, total weeks, number of weekdays (Mon--Fri), and number of weekend days. Check "Exclude weekends" to count only business days. US federal holidays are not automatically excluded — deduct them manually if needed for legal or contract deadlines.
2026 US federal holidays: New Year's Day Jan 1, MLK Day Jan 19, Presidents' Day Feb 16, Memorial Day May 25, Juneteenth Jun 19, Independence Day Jul 3 (observed — Jul 4 falls on Saturday), Labor Day Sep 7, Columbus Day Oct 12, Veterans Day Nov 11, Thanksgiving Nov 26, Christmas Dec 25. Total = 10 official federal holidays.
A date calculator is an online tool used to calculate the number of days, weeks, months, years, weekdays, or business days between two dates.
Weekdays include Monday through Friday and exclude Saturday and Sunday weekends.
Yes. You can calculate total days or exclude weekends to calculate only working days.
Yes. Business day calculations can exclude USA federal holidays for accurate workday counting.
The Gregorian calendar is the modern calendar system used in the United States and most countries worldwide.
A typical USA work year contains around 260 business days excluding weekends, depending on holidays.
Yes. You can add or subtract days, weeks, months, or years from any date.
Yes. Leap years are automatically included for accurate date calculations.
Yes. The calculator can determine exact age in years, months, and days.
Yes. The online date calculator is completely free to use on desktop, tablet, and mobile devices.
Business day calculations help companies, employees, HR teams, and project managers accurately track deadlines and working schedules.
Yes. You can calculate the number of days remaining until birthdays, holidays, vacations, exams, and events.
Yes. The calculator is fully optimized for mobile phones, tablets, and desktop computers.
Calendar days include all days, while business days exclude weekends and sometimes holidays.
Yes. The calculator can show how many Saturdays and Sundays occur between two dates.