Time Duration Calculator

Need to know how many working days are left until your project deadline? How many hours between two timestamps for a timesheet? How many weeks since a specific date? Enter your start and end dates, choose your unit, and get the exact answer — including or excluding weekends.

Common Time Calculations (Quick Reference)

For any specific date range, use the calculator above — the table shows approximate values only.

How to Use This Time Duration Calculator

1. Set your start date — click the date picker or type in the format shown
2. Set your end date — must be the same as or later than the start date
3. Set times (optional) — the default is 09:00 start to 17:00 end; change these if you need hour/minute precision
4. Choose your output unit — days, hours, minutes, seconds, or weeks
5. Toggle "Exclude weekends" to get business days instead of calendar days
6. Click Calculate Duration — results appear instantly with a full breakdown
7. Download the report — save your calculation as a text file for records or sharing

Business Days vs Calendar Days: When It Matters

Calendar days count every day including weekends. Business days count only Monday through Friday. The difference can be significant for planning:

Project managers and HR teams should always use business days for deadlines and contract durations. Using calendar days will overstate your available working time by roughly 28%.

Practical Use Cases for This Calculator

Project managers: Calculate working days between kickoff and delivery to set realistic sprint schedules. Enter your project start and launch date with weekends excluded to get actual working time available.

HR and payroll teams: Measure probation periods, notice periods, and contract durations. A 90-day probation period starting on March 3rd ends on June 1st — 65 business days of actual working time.

Freelancers and contractors: Track billable hours and days on projects. Enter shift start and end times to calculate exact hours worked for timesheet purposes.

Legal and compliance: Many legal notice periods and filing deadlines are stated in calendar days. Use the calendar day mode and count from the official trigger date.

Events and countdowns: How many days until your flight, wedding, or product launch? Enter today and your target date for an instant countdown.

The Built-In Duration Unit Converter

Alongside the main date calculator, this page also includes a standalone unit converter for time durations. Enter any number and convert it between seconds, minutes, hours, days, and weeks.

Quick reference:

• 1 hour = 3,600 seconds
• 1 day = 86,400 seconds = 1,440 minutes
• 1 week = 7 days = 168 hours = 10,080 minutes
• 1 year = 365 days = 8,760 hours = 525,600 minutes

The converter works independently from the date calculator — enter a number, select the source unit and target unit, and get the converted value instantly.

Understanding the Detailed Breakdown

After calculating, the results show your answer in the selected unit plus a detailed breakdown in days, hours, minutes, and seconds. For example, a duration of 2 days and 6 hours would show:

• Result in hours: 54 hours
• Breakdown: 2 days, 6 hours, 0 minutes, 0 seconds
• Business days (if weekend exclusion is on): shows separately

This full breakdown is useful when the simple unit answer does not give the complete picture.

Downloading Your Calculation Report

Click the Download Report button after calculating to save a text file containing your start date, end date, selected unit, final result, and full breakdown. This is particularly useful for:

• Keeping records of time calculations for legal or HR purposes
• Including in project documentation
• Sharing with colleagues or clients as a clear timestamp reference

How the Business Day Calculation Works

When "Exclude weekends" is selected, the calculator iterates through each date in the range and counts only days that fall on Monday through Friday. Saturday and Sunday are skipped entirely. Public holidays are not excluded — this calculator counts weekdays only, not country-specific holidays.

If you need to account for specific national holidays (e.g., for a formal contract period), subtract the number of applicable holidays from the business day result manually.

Time Duration Calculator — Help & FAQs

How many business days are in a year?

A standard 365-day year has approximately 261 weekdays (Monday–Friday). The exact count varies slightly by year depending on how weekends fall. Use this calculator with January 1 to December 31 of any year, with "Exclude weekends" enabled, for the exact count.

Can I calculate hours between two times on the same day?

Yes. Enter the same date for start and end, set different times, and select "Hours" as your unit. For example: same-day 9:00 AM to 5:30 PM returns 8.5 hours (510 minutes).

How many days are there in a specific month?

Enter the first and last day of the month in the calculator. January 1 to January 31 returns 30 days (the difference), meaning January has 31 days total. Alternatively: Jan/Mar/May/Jul/Aug/Oct/Dec = 31 days; Apr/Jun/Sep/Nov = 30 days; Feb = 28 days (29 in a leap year).

Does the business day calculator include public holidays?

No. This calculator excludes only Saturdays and Sundays. Public holidays are not removed automatically because they vary by country and region. Subtract the applicable holidays from the business day result manually for a country-specific working day count.

What if my start date is after my end date?

The calculator shows an error and does not proceed. Swap your start and end dates and try again.

Is this calculator accurate to the second?

Yes. The calculator uses system datetime arithmetic for precise results. When you include time fields (not just dates), the duration is calculated to the exact second.

Can I use this for project timesheets?

Yes. Enter your shift start and end date/times and set the unit to "Hours" or "Minutes" for timesheet calculations. Download the report for a record you can include in billing or payroll documentation.