Date Calculator
Use this free Date Calculator to find the days between two dates, add or subtract days from a date, or count business days while excluding weekends.
Find the exact number of days, weeks, and years between two dates.
Add or subtract a number of days from a starting date to find the resulting date.
Count only working days (Monday–Friday) between two dates, excluding weekends.
How to Use the Date Calculator
Pick a mode
Choose "Days Between Dates" to compare two dates, "Add/Subtract Days" to project a future or past date, or "Business Days" to count working days only.
Enter your date(s)
Use the date picker to select your dates. For the add/subtract mode, also enter the number of days and choose add or subtract.
Click Calculate
Get your exact result instantly, whether that's a day count, a resulting date, or a business-day total.
How This Date Calculator Works
A date calculator handles a surprisingly tricky piece of everyday math: counting across months of different lengths, leap years, and weekends. This date calculator covers the three situations people run into most, finding the days between two dates, projecting forward or backward from a date, and counting only business days.
Finding the Days Between Two Dates
This mode compares two dates and returns both a years/months/days breakdown and a total day count. It works regardless of which date comes first, the calculator automatically treats the earlier date as the starting point.
Example: Between January 15, 2025 and June 3, 2025, this date calculator returns 4 months and 19 days, or 139 total days. Manually counting across five different months, including February, would be easy to get wrong by a day or two.
Adding or Subtracting Days From a Date
This mode answers a common planning question: what date falls exactly N days from now (or from any starting date)? It's the math behind due dates, contract terms, and shipping estimates.
Example: Adding 90 days to March 1, 2025 lands on May 30, 2025, not a round "3 months later" the way people often estimate in their head, since months don't all have the same number of days.
How a Date Calculator Counts Business Days
Business days mode counts only Monday through Friday between two dates, skipping Saturday and Sunday entirely. This calculator checks the day of the week for every single day in the range and only counts it if it falls on a weekday.
Note that this business day count does not automatically exclude public holidays, since holiday calendars vary by country and organization. For holiday-specific scheduling, check your local or company calendar alongside this calculator's weekday count.
Why Manual Date Math Goes Wrong
Manual date counting fails most often at month boundaries. February has 28 days in most years but 29 in a leap year, and April, June, September, and November have 30 days while the rest have 31. According to the timeanddate.com leap year reference, a year is a leap year if it's divisible by 4, except century years, which must be divisible by 400. This date calculator accounts for all of that automatically, so a date months or years away is calculated exactly, not estimated.
Common Uses for a Date Calculator
People use a date calculator for contract deadlines, project timelines, shipping and delivery estimates, pregnancy due dates, visa or lease durations, and countdowns to events. Businesses specifically rely on the business-days mode for calculating service level agreements (SLAs), payment terms like "net 30 business days," and staffing schedules. Government agencies, including guidance published by the USA.gov federal holidays page, often define legal deadlines in business days specifically, which is why separating weekday counts from calendar day counts matters for compliance.
Why Use Our Date Calculator
Instant Results
Get your answer the moment you click Calculate, no waiting or reloading.
3 Calculation Modes
Date difference, add/subtract days, and business days, all in one place.
100% Private
Everything runs in your browser. Your dates are never stored or sent anywhere.
Works on Any Device
Fully responsive design, so it's just as easy to use on mobile as on desktop.
Handles Leap Years
Correctly accounts for varying month lengths and leap years automatically.
Completely Free
No sign-up and no limits. Use it as often as you need, at no cost.
Frequently Asked Questions
Use the "Days Between Dates" mode of this date calculator, enter both dates, and it returns the exact difference in years, months, days, and total days.
Yes, both the start and end dates are included in the count if they fall on a weekday.
No, it only excludes Saturdays and Sundays. Public holidays vary by country and organization, so check your specific calendar for holiday exclusions.
Yes, the "Add/Subtract Days" mode has a dropdown to choose subtract, which calculates a date that many days before your starting date.
Yes. All calculations use exact calendar dates, so leap years and varying month lengths are automatically accounted for without any manual adjustment.
No. All calculations happen locally in your browser, and nothing you enter is stored or transmitted.
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