How do I count the days between two dates?

Subtract the earlier date from the later date. In days, this is the difference in milliseconds divided by 86,400,000 (ms per day). For example, from January 1 to March 1 (non-leap year) is 59 days. This calculator does that arithmetic instantly and also breaks the result down into weeks, months, and business days.

How many business days are between two dates?

Business days exclude Saturdays and Sundays (and optionally public holidays). The calculator counts every calendar day in the range and subtracts those falling on weekends. For example, a period of 14 calendar days spanning two full weeks contains exactly 10 business days. Holiday exclusions vary by country and are not currently included.

Does the calculator include or exclude the start and end dates?

By default, the calculator counts from the start of day 1 to the end of the last day — meaning it includes both the start and end dates. You can toggle this with the 'Include end date' option. Excluding the end date gives you the number of full days elapsed; including it gives you the total days in the span (e.g., from Monday to Friday is 4 elapsed days or 5 total days).

How many weeks between two dates?

Divide the total days by 7. The result is the number of complete weeks plus any remaining days. For example, 30 days is 4 weeks and 2 days. This calculator shows both the total weeks figure and the remainder so you can see the full picture at a glance.

How do I calculate months between two dates?

Calculating exact months is trickier than days because months have different lengths. The calculator counts complete calendar months (e.g., February 15 to May 15 = exactly 3 months) and shows the remaining days separately. This gives you a result like '3 months and 12 days' rather than a decimal fraction of a month.

📅 Days Between Dates — Count Days, Weeks & Months Between Any Two Dates

Instantly find the number of days, weeks, months, and business days between any two dates.

Start Date

End Date

Include end date Business days only

Date Facts

365 days

In a regular year

366 days

In a leap year (every 4 years)

252 days

Average working/business days per year

604,800

Seconds in one week

86,400

Seconds in one day

How It Works

How to Count Days Between Two Dates

At its core, the calculation subtracts one date from another. In JavaScript (and most programming languages), dates are stored as milliseconds since January 1, 1970. The difference in milliseconds divided by 86,400,000 gives the number of days.

Weeks are days ÷ 7. Months are more complex — they require counting full calendar months between the two dates and then the remaining days separately, since months have different lengths.

Business days require checking each individual day in the range and excluding Saturdays and Sundays. For project planning purposes, you can treat this calculator's business day count as correct for countries where Mon–Fri are working days.

Days in each month

Jan

Feb

28/29

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Feb has 29 days in leap years (divisible by 4, except century years unless also divisible by 400).

Common Date Spans at a Glance

Quick reference for frequently needed date counts.

1 week

7 days

5 business days

1 month

~30 days

~22 business days

1 quarter

~91 days

~65 business days

6 months

~182 days

~130 business days

1 year

365 days

~252 business days

2 years

730 days

~504 business days

Frequently Asked Questions

Subtract the earlier date from the later date. In days, this is the difference in milliseconds divided by 86,400,000 (ms per day). From January 1 to March 1 (non-leap year) is 59 days. This calculator does that arithmetic instantly and also breaks the result down into weeks, months, and business days.

Business days exclude Saturdays and Sundays. The calculator counts every calendar day in the range and subtracts those falling on weekends. A period of 14 calendar days spanning two full weeks contains exactly 10 business days. Public holiday exclusions vary by country and are not currently included — subtract them manually for project planning purposes.

By default, the calculator includes both the start and end date in its count. You can toggle the "Include end date" option to change this. Excluding the end date gives you elapsed days; including it gives you the total span in days. Example: Monday to Friday is 4 elapsed days or 5 total days.

Divide the total days by 7. The result is complete weeks plus remaining days. 30 days = 4 weeks and 2 days. The calculator shows both figures. For project planning, it's often more useful to round up to the next complete week to ensure you have buffer time.

Calculating exact months is trickier than days because months have different lengths. The calculator counts complete calendar months (February 15 to May 15 = exactly 3 months) and shows remaining days separately, giving a result like "3 months and 12 days" rather than a decimal.

How Many Business Days Between Two Dates?

For contracts, project timelines, and legal deadlines, business days are what matter. Weekends don't count. If a contract says "deliver in 10 business days" and you start on a Monday, the deadline is two weeks away (the following Friday), not 10 calendar days later. This calculator counts business days by checking every day in the range individually and skipping Saturdays and Sundays — giving you an accurate count for planning purposes.

Days Between Dates for Project Planning and Deadlines

Project managers use date-span calculators to build timelines, set milestones, and calculate buffer time. A useful technique: calculate the total calendar days between your start and your hard deadline, then subtract weekends and known holiday dates to get your available business days. Divide that by the number of tasks to find how many working days each task can consume without pushing the deadline.

How Many Days Until My Vacation, Event, or Holiday?

Enter today's date as the start and your event date as the end to count down to any future date. The calculator shows the total days remaining, the weeks and days breakdown, and the number of working days — useful if you're tracking how many working days remain before an annual leave period. For a dedicated countdown timer with presets for major holidays, use the Days Until Calculator.