📅 Date Tool

Free Online Date Calculator

Calculate date differences, add or subtract days, find weekdays, time until events and much more — instantly.

Date Difference Add / Subtract Days Working Days Days Until Event Day of Week Week Number
✅
Result
—

What Is a Date Calculator and Why Use One?

A date calculator is an essential online tool that allows you to perform a wide range of calculations involving calendar dates and time periods. Whether you need to find out exactly how many days remain until an important event, calculate the number of working days between two dates, figure out what date falls 90 days from today, or simply discover which day of the week a particular date falls on — a date calculator makes all of these tasks instant and error-free.

Manual date calculations are surprisingly tricky. Different months have different numbers of days, leap years add an extra day to February every four years, and counting working days while excluding weekends requires careful attention. Even a small mistake can cause you to miss a deadline, miscalculate a contract period, or misplan a project timeline. Our date calculator handles all of this complexity automatically, so you get precise results every time.

This tool is useful for a wide variety of everyday and professional situations — from planning personal events and holidays to calculating legal deadlines, contract durations, project milestones, loan periods, visa validity, probation periods, and much more. It supports four powerful calculation modes, each designed to answer a different type of date-related question.

📊
Date Difference
Find exact days, weeks, months and years between any two dates including working days.
➕
Add / Subtract
Add or subtract any combination of years, months and days to get a future or past date.
⏳
Days Until Event
Count down to birthdays, exams, weddings, holidays or any important upcoming date.
📆
Day of Week
Find out which day of the week any date falls on, along with week number and quarter.
💼
Working Days
Calculate business days between two dates automatically excluding weekends.
🔒
100% Private
All calculations run in your browser. No data is ever sent to any server.

How to Use This Date Calculator

Our date calculator offers four distinct modes, each solving a different type of date problem. Here is how to use each one effectively to get the most accurate and useful results:

  1. 1
    Date Difference — How many days between two dates?Select your start date and end date using the date pickers. Choose whether to exclude weekends for a working-days count. Hit Calculate and instantly see the difference in years, months, weeks, days, hours and minutes — along with working days.
  2. 2
    Add / Subtract — What date is X days from now?Pick your starting date, then enter the number of years, months and days you want to add or subtract. Choose Add or Subtract from the dropdown and click Calculate to instantly find the resulting date.
  3. 3
    Days Until Event — Countdown to a special dateType your event name (optional), pick the event date, and choose whether to count from today or a custom start date. Get a full countdown in days, weeks, and months until your event arrives.
  4. 4
    Day of Week — Which day does a date fall on?Simply select any date and click Calculate to find out the exact day of the week, week number of the year, quarter, and whether the day is a weekday or weekend.
  5. 5
    Copy your resultsOnce calculated, use the Copy Result button to copy the result to your clipboard for easy sharing or pasting into documents, emails or spreadsheets.

Common Uses for a Date Calculator

Date calculators are used every day by millions of people across a huge range of personal and professional scenarios. Understanding what the tool can do for you helps you get the most out of it:

  • Legal and contract deadlines: Calculate exactly when a 30-day, 60-day or 90-day notice period expires, or find out when a fixed-term contract ends.
  • Pregnancy due dates: Add 280 days (40 weeks) to the first day of the last menstrual period to estimate a due date, or calculate how many weeks along a pregnancy is.
  • Visa and passport validity: Calculate whether your passport or visa will still be valid on your travel dates, including the 6-months-validity rule many countries require.
  • Project management: Find the number of working days available in a sprint or project phase, or calculate when a project will complete given a start date and duration.
  • Finance and loans: Calculate interest periods, loan maturity dates, payment due dates, or the exact number of days in a billing cycle.
  • Age and anniversaries: Find out exactly how many days until a birthday, wedding anniversary or other milestone, or how many days old you are today.
  • Academic deadlines: Count working days until an assignment submission, exam date or semester start — helping students and educators plan their schedules.
Frequently Asked Questions
The date difference calculator computes the exact number of calendar days between two dates by comparing their timestamps. It then converts this total into years, months, weeks, days, hours and seconds for a comprehensive breakdown. For working days, it iterates through each day in the range and skips Saturdays and Sundays.
Yes — all calculations fully account for leap years. February 29 is treated as a valid date in leap years, and the day count automatically adjusts when a leap year falls within the date range being calculated. This ensures accuracy for multi-year calculations.
In this calculator, working days are Monday through Friday. Saturday and Sunday are treated as weekend days and excluded when you choose the "working days only" option. Public holidays are not excluded as these vary by country and region — you would need to subtract those manually if required.
Yes — the calculator can handle dates across a very wide range, including dates hundreds of years in the past or future. The JavaScript Date object used for calculations supports dates from the year 100 AD to well beyond the year 9999, making it suitable for virtually any date calculation you might need.
Yes. When you add or subtract months, the calculator correctly handles months of different lengths. For example, adding one month to January 31 gives February 28 (or 29 in a leap year) since February does not have 31 days — it automatically adjusts to the last valid day of the resulting month.
Completely. Every calculation runs entirely within your browser using JavaScript. No dates, event names or any other data you enter are sent to any server or stored anywhere. Your information stays on your device at all times.