How do I calculate days between two dates?

Enter your start date and end date in the 'Days Between Two Dates' section above. The calculator instantly shows the total calendar days, weeks, and business days (weekdays only) between the two dates.

How many days until a specific date?

Use the 'Days Between Two Dates' section with today as the start date and your target date as the end date. The result shows exactly how many calendar days and business days remain until that date.

How do I add business days to a date?

Use the 'Add or Subtract from a Date' section. Enter your start date, the number of days to add, and select 'Add'. The result displays both the calendar date and the count of business days (Monday through Friday) in that range.

Date Calculator - Add Days, Weeks, Months to Any Date

28-Day Intervals

From

90-Day Count

From

Quick Shortcuts

Add or Subtract from a Date

Start Date

Amount

Direction

Days Between Two Dates

Start Date

End Date

What Day of the Week Was...?

Pick a Date

Date Calculator Guide

How to Use This Date Calculator

This free date calculator helps you add or subtract days, weeks, months, or years from any date. It also calculates the exact number of days between two dates, counts business days (weekdays), and tells you the day of the week for any date.

Common Use Cases

Contract deadlines: Find the exact date 30, 60, or 90 days from a signing date.
Project planning: Calculate delivery dates by adding weeks or months to a start date.
Legal deadlines: Determine filing deadlines, notice periods, and statute of limitations dates.
Travel planning: Count the days until your trip or calculate return dates.
Pregnancy due dates: Add 40 weeks (280 days) from the last menstrual period.
Financial calculations: Determine maturity dates, payment schedules, and interest periods.
Warranty tracking: Find when a 1-year or 2-year warranty expires.

Business Days vs. Calendar Days

Calendar days include every day (Monday through Sunday), while business days count only weekdays (Monday through Friday). This distinction matters for contracts, shipping estimates, and legal deadlines. Our calculator shows both so you always have the information you need.

Adding Months and Years

When adding months, the calculator preserves the day of the month when possible. For example, adding 1 month to January 15 gives February 15. If the target month has fewer days (e.g., adding 1 month to January 31), the result is clamped to the last day of that month (February 28 or 29).

Leap Years

A leap year occurs every 4 years, except for years divisible by 100 -- unless also divisible by 400. This means 2024 and 2028 are leap years, but 2100 is not. The calculator handles leap years automatically in all calculations.

Date Calculator User Guide

This date calculator is designed for anyone who needs to work with dates precisely -- project managers tracking deadlines, legal professionals counting filing periods, HR teams calculating employee milestones, or anyone planning around a specific calendar date. All calculations run instantly in your browser with no data stored or transmitted.

How to Use Each Section

The 28-Day Intervals section shows recurring 28-day cycles from a chosen start date, which is useful for medication schedules, payroll cycles, or fitness programs. The 90-Day Count section visualizes a 90-day window, commonly used for probation periods and visa calculations. Use the Quick Shortcuts to jump to common offsets like 30, 60, 180, or 365 days from today.

The Add or Subtract section lets you pick any start date and add or remove a precise number of days, weeks, months, or years. The Days Between section calculates the exact gap between any two dates in calendar days, weeks, and business days. The Day of the Week section tells you what day any historical or future date falls on.

Business Days vs. Calendar Days

This distinction trips up many people. Calendar days count every day including weekends and holidays. Business days count only Monday through Friday, excluding weekends. Most legal deadlines, shipping estimates, and corporate policies use business days, while rental agreements, age calculations, and medical timelines typically use calendar days. This calculator shows both counts so you always have the right number.

Common Use Cases

Calculate contract expiration dates by adding the term length to the signing date. Determine how many business days remain until a regulatory filing deadline. Find the exact date 90 days from an employee's start date for a probation review. Count the days between a lease signing and move-in date. Plan project milestones by adding weeks or months to your kickoff date. Calculate your exact age in days for insurance or actuarial purposes.

Frequently Asked Questions

Does the calculator account for leap years?

Yes. The calculator correctly handles leap years in all operations. February 29 is included when adding days through a leap year, and year-based calculations account for the extra day. Leap years occur every four years except for century years not divisible by 400.

What happens when I add one month to January 31?

The calculator clamps to the last valid day of the target month. Adding one month to January 31 gives February 28 (or February 29 in a leap year). This matches the behavior of standard date libraries and avoids producing invalid dates.

Does the business day count exclude holidays?

The business day calculation excludes weekends (Saturday and Sunday) but does not exclude public holidays, since holidays vary by country, state, and organization. For a precise business-day count that includes holiday exclusions, subtract the holidays that fall on weekdays within your date range from the result shown.

Can I calculate dates far in the future or past?

Yes. The calculator works with any date supported by your browser's date system, which typically covers years from 0001 to 9999. You can calculate dates centuries in the past or future with full accuracy.

What is the difference between adding 4 weeks and adding 1 month?

Four weeks is always exactly 28 days. One month moves to the same day of the next month, which can be 28, 29, 30, or 31 days depending on the starting month. For February to March, one month is 28 or 29 days; for January to February, it is 28 or 29; for March to April, it is 31 days. Use weeks when you need a fixed interval, and months when you need calendar-month alignment.