Days Between Dates Calculator – Calendar Days, Business Days and More
The Days Between Dates Calculator on MyTimeCalculator helps you measure time between dates in a flexible way. You can start with a simple difference in days and weeks, then drill down into business days, working hours, multiple date ranges and preset scenarios such as age or 30 days from today.
Instead of building complex formulas in a spreadsheet, this tool centralizes the logic for you. It is useful for planning projects, tracking leave, understanding service periods, estimating deadlines and checking age or anniversary milestones.
How the Basic Date Difference Mode Works
The Basic Difference tab focuses on calendar time between a start date and an end date. You can choose to include or exclude the end date. Inclusive ranges are common when describing periods such as “from 1 January to 31 January inclusive,” while exclusive ranges are helpful when you want the number of full days between two timestamps.
If you turn on time of day, the calculator uses hours and minutes as well. This is ideal when you need an exact difference for things like rental windows, service windows or system logs. The output includes total days, total hours and a breakdown into days, hours and minutes.
Days, Weeks, Months and Years
Date differences can be expressed in several ways. The calculator shows:
- Total days between start and end
- Weeks and days by dividing the total by seven
- Calendar years, months and days using a calendar-based breakdown
- Approximate months and days using an average days-per-month conversion
It also displays the weekday name for both start and end dates so you can quickly see how periods align with weekends or particular weekdays.
Business Days and Working Hours
The Business Days & Work Hours tab helps you measure working time rather than just calendar days. You set start and end dates and choose whether to include the end date, then define what counts as a working day.
You can exclude weekends in one click or build a custom pattern of working weekdays. This is especially useful for organizations with non-standard workweeks, such as Sunday–Thursday schedules. You can also list holidays so that national or company days off are excluded from the business day count.
Once working days are defined, the calculator multiplies the number of business days by your working hours per day to estimate total working hours in the period. It also reports how many days were excluded as weekends, holidays or other non-working weekdays.
Multiple Ranges and Cumulative Totals
Real-life scenarios often involve multiple date ranges: staggered project sprints, separate leave blocks, several billing periods or repeating service windows. The Multiple Ranges tab lets you enter several start and end dates with individual inclusion choices for each end date.
The calculator then counts days in each range and adds them up. It reports how many ranges were valid, the total days across all ranges and an average days-per-range figure. This gives a simple summary of scattered time windows without manually adding each result.
Presets, Forward Dates and Age Calculations
The Presets & Age tab is designed for quick everyday questions:
- How many days are there in the next 30, 60 or 90 days from today?
- What is someone’s age in years, months and days on a certain date?
You can fix the “today” anchor date manually or allow the tool to use the current date from your device. The age calculation takes a date of birth and an as-of date and produces age in calendar years, months and days, along with the total days lived.
Supported Date Conventions and Inputs
The calculator uses standard calendar dates in the browser’s local time zone. When you enter values through date pickers, the input format is normalized internally, so you do not need to worry about regional formatting. Holidays are entered using an ISO-style format such as 2025-12-25 and can be separated by commas or new lines.
All calculations are numeric approximations based on these calendar values. For specialized legal, payroll or financial rules, you should always check local regulations and official formula definitions.
Use Cases for Days Between Dates
- Planning project durations and comparing timelines
- Estimating business days between contract start and end dates
- Calculating leave balances and time off across multiple periods
- Checking how long it has been since an event or until a deadline
- Computing age or anniversary dates to the exact day
- Summing non-contiguous service periods across multiple ranges
Tips for Reliable Date Difference Results
- Decide whether you want inclusive or exclusive ranges before entering dates.
- Use time-of-day inputs when you care about hours and minutes, such as rental windows.
- In business mode, make sure holidays are entered accurately and check your weekday pattern.
- For formal or legal calculations, confirm whether your organization uses inclusive or exclusive counting and which days count as working days.
Days Between Dates Calculator FAQs
Frequently Asked Questions About Date Differences
Learn how to use the Days Between Dates Calculator for basic differences, business days, multiple ranges and age calculations.
Inclusive ranges count both the start and the end date, while exclusive ranges count the full days between them. For example, from 1 January to 2 January inclusive is 2 days, but exclusive it is 1 day. The calculator lets you choose the convention that matches your use case.
Business days typically exclude weekends and holidays. The basic difference shows the raw number of calendar days, while business mode filters out non-working days and focuses on the days that count as workdays for your schedule or policy.
You can manually enter the same start and end dates in both tabs to compare calendar days with business days. This is helpful when you want to know both the total time period and the working time inside that period.
Age depends on whether the birthday has occurred yet in the current year. The calculator uses full calendar comparisons of year, month and day, so it can properly account for whether the current date is before or after the birthday and return an accurate age in years, months and days.
Enter each holiday date in a YYYY-MM-DD format, separated by commas or new lines. The calculator matches these dates against the range and excludes them when counting business days and working hours, even if they fall on a normal workday.
Yes. Use multiple ranges to enter each leave period or break separately. The calculator sums the days across all valid ranges and gives you a total and an average per range, so you do not need to add each period manually.