How do I calculate the number of days between two dates?

Enter your start date and end date in the calculator. It instantly shows the exact number of days between them, plus the breakdown in weeks, months, and years. The date difference calculator accounts for varying month lengths and leap years.

How do I add days to a date?

Use the 'Add/Subtract Days' mode. Enter your starting date and the number of days to add. The calculator shows the resulting date. You can also add weeks, months, or years to any date.

How do I calculate business days between two dates?

The calculator automatically shows business days (excluding weekends) between your selected dates. Business days are Monday through Friday. For more accuracy, you can also exclude holidays from the count.

How many working days are in a year?

A standard year has approximately 260-262 working days (52 weeks × 5 days), depending on which day January 1 falls on. This excludes weekends but not holidays. Subtract your country's public holidays for the exact count.

How do I subtract days from a date?

Use the 'Add/Subtract Days' mode and enter a negative number, or use the subtract option. Enter the starting date and number of days to subtract. The calculator shows what date it was that many days ago.

How do I find the date from today plus X days?

The calculator defaults to today's date. Simply enter the number of days you want to add. For example, adding 30 days from today shows the date exactly one month ahead (approximately).

How do I calculate weeks between two dates?

Enter both dates and the calculator shows total weeks between them. It divides the total days by 7 and shows both complete weeks and remaining days for precision.

How accurate is this date calculator?

Our date calculator is highly accurate, properly handling leap years, varying month lengths (28-31 days), and century boundaries. It uses the Gregorian calendar system used worldwide.

Can I calculate months between two dates?

Yes, the calculator shows the difference in complete months plus remaining days. It accounts for varying month lengths to give you precise results.

How do I use this for project deadline calculation?

Enter your project start date and end date to see total days available. Use business days for work scheduling to exclude weekends. For country-specific workday counting, cross-reference the federal-holiday list (see sources) and deduct those from your business-day total. For buffer planning, add 10-15% contingency to your calculated duration.

What's the difference between calendar days and business days?

Calendar days count every day including weekends and holidays. Business days (also called working days) exclude Saturdays and Sundays — and often public holidays too. Example: February 1 to February 28, 2026 is 27 calendar days but only 20 business days (4 weekends removed). Legal and commercial contracts sometimes specify 'X days' without clarifying — best practice is to check the contract's definitions section or ask in writing. US federal government uses 'calendar days' unless stated otherwise; UK law often specifies 'working days' in financial regulations.

How do I calculate working days excluding holidays in the US, UK, Canada or Australia?

Start with business days (weekdays only), then subtract the public holidays that fall within your range. US: ~11 federal holidays/year (New Year's Day, MLK Day, Presidents Day, Memorial Day, Juneteenth, Independence Day, Labor Day, Columbus Day, Veterans Day, Thanksgiving, Christmas). UK: 8 bank holidays in England and Wales (plus St Andrew's Day in Scotland, St Patrick's Day in Northern Ireland). Canada: 5 federal statutory holidays but provinces add their own (Ontario 9, BC 10, etc.). Australia: 7 national plus state-specific holidays (Victoria adds Melbourne Cup Day, etc.). See our sources for official lists.

What date format should I use for international communication?

For unambiguous international use, always use ISO 8601: YYYY-MM-DD (e.g., 2026-04-24). This sorts chronologically as text and eliminates the US MM/DD/YYYY vs rest-of-world DD/MM/YYYY confusion — '04/05/2026' means April 5 in the US but May 4 in UK/CA/AU. When writing for a mixed audience, spell out the month: 24 April 2026. Most programming languages, databases and APIs default to ISO 8601. UK/Canadian/Australian government forms increasingly prefer it. In the US, MM/DD/YYYY is still dominant in everyday contexts despite ISO being the formal standard.

How do I count days for legal deadlines (contracts, court filings, notice periods)?

Legal day-counting is jurisdiction-specific. US federal courts (FRCP Rule 6): the start day is generally excluded, the deadline day is included; if the deadline falls on a weekend or legal holiday, it extends to the next business day. 'Days' usually means calendar days unless the rule says 'business days'. UK civil courts (CPR Rule 2.8): similar — count 'clear days' excluding start and end for periods of 5 days or less. Canada varies by jurisdiction; provincial Rules of Civil Procedure typically exclude first day. Australia: state-specific. For any real legal matter, verify with the applicable court rules or consult counsel — our calculator is general-purpose and doesn't encode jurisdiction-specific counting conventions.

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Date Calculator

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Start Date

End Date

Include end date in count

Total Duration

days between dates

Years

Months

Days

Work Days Breakdown

Business Days

Weekend Days

Total Weeks 0

Input Values

Start Date

End Date

lightbulb Tips

•Business days = Mon-Fri only
•Toggle to include/exclude end date
•Use negative numbers to subtract
•1 year ≈ 365 days (366 in leap year)

calendar_month Quick Reference

1 week 7 days

1 month (avg) 30.44 days

1 year 365 days

Leap year 366 days

Work days/year ~260 days