Days Between Dates

Days Between Dates Calculator — Business Days, Milestones & Date Math

Enter any two dates and instantly see the exact difference in days, weeks, months, and years — all at once in one screen. Switch to business days mode to exclude weekends and national holidays for 7 countries. Find your next 1,000-day milestone, track deadline urgency, or calculate what date falls 90 days from today.

No other free calculator shows all time units simultaneously, includes national holidays for Brazil, the US, Germany, France, Spain, Italy, and Portugal, and automatically surfaces upcoming milestones. This tool does all three.

How to Use the Days Between Dates Calculator

Three seconds to get every result you need:

1. Pick your start and end dates — click each date field and type or select from the calendar picker. The result updates instantly as you type.
2. Choose your holiday calendar — select your country from the dropdown to exclude national holidays from the business days count. Leave it on "None" for calendar days only.
3. Read all results at once — total days (large), weeks, hours, minutes, seconds, and the years/months/days breakdown all appear simultaneously. No clicking between tabs.

To add or subtract days from a date: switch to the Add / Subtract Days tab, enter a base date and a number of days, choose direction (forward or backward), and toggle business days if needed.

Days Between Dates Calculator Examples

Edge case — include end date toggle:

Start: Jan 1 → End: Jan 31 (default, end excluded) = 30 days
Start: Jan 1 → End: Jan 31 (end included)          = 31 days

Edge case — business days vs. calendar days for the same period:

Start: Dec 20, 2024 → End: Jan 10, 2025
Calendar days: 21
Business days (US): 13  ← Christmas + New Year + weekends reduce by 8
Business days (BR): 11  ← Brazilian holidays add 2 more exclusions

Calendar Days vs. Business Days — What's the Difference?

Calendar days count every day of the week, including weekends and public holidays. 30 calendar days always means exactly 30 days regardless of when they fall.

Business days (also called working days) exclude weekends (Saturday and Sunday) and, for the selected country, national public holidays. The same 30-day period may contain only 20–22 business days depending on how many weekends and holidays fall within it.

The key rule: always verify the specific contract or regulation to determine whether a deadline is in calendar days or business days. When uncertain, calculate both and use the business days result as the conservative estimate.

Common Use Cases

• Legal and contract deadlines: Counting precise calendar or business days for notice periods, payment deadlines, statutory timeframes, or contract terms where the count matters legally.
• Employment and payroll: Calculating vacation entitlement, notice period length, severance, or payroll cutoffs that depend on exact day counts.
• Project management: Finding how many working days remain before a project deadline, sprint duration, or milestone date.
• Personal milestones: Discovering exactly when a relationship, sobriety streak, fitness goal, or personal project hits 100, 500, or 1,000 days — dates people actually share and screenshot.
• Financial planning: Net 30 / net 60 / net 90 payment terms, settlement dates, bond maturity, and loan deadlines that depend on precise day counts.
• Travel and logistics: Visa validity windows, entry permit durations, customs deadlines, or shipment tracking in calendar days.

Automatic Milestones — The Feature Most Calculators Miss

After you enter two dates, this calculator automatically computes six upcoming milestones from the start date:

• 100 days — a quick early milestone for projects, relationships, and health goals
• 1 year — the first annual anniversary
• 500 days — roughly 16 months, popular for couples and long-term goals
• 2 years — a key renewal or reflection point for most commitments
• 1,000 days — approximately 2 years and 9 months. A viral, highly shareable milestone that no other free calculator surfaces automatically.
• 5 years — a major long-term milestone for any goal or relationship

Milestones that have already passed appear grayed out. Upcoming ones show the exact future date in your locale's date format.

Common Mistakes When Counting Days

• Confusing "calendar days" with "business days": A contract saying "30 days" typically means 30 calendar days, not 30 business days. Always read the original document before choosing which mode to use.
• Forgetting to toggle "include end date": By default, the end date is excluded (standard for duration calculations). From Jan 1 to Jan 31 = 30 days. If you need to count both the first and last day, enable the toggle.
• Using only federal holidays for the US: This calculator uses US federal holidays. Private employers may observe additional holidays (e.g., the day after Thanksgiving). For HR purposes, always verify against the specific company calendar.
• Treating "90 days" as exactly 3 months: Three calendar months can range from 89 to 92 days depending on which months they span. 90 calendar days and "3 months" are not interchangeable.

Frequently Asked Questions

How do I calculate days between two dates?

Subtract the earlier date from the later date — the result is the number of calendar days between them. This calculator does it automatically for any two dates and simultaneously shows the result in days, weeks, months, years, hours, minutes, and seconds. Just enter the two dates and all units appear instantly.

Does the calculator include the start date and end date?

By default, the start date is included and the end date is excluded — the standard convention for duration calculations. From January 1 to January 31 = 30 days, not 31. Enable the "Include end date" toggle to count both endpoints, which gives 31 days for that same range. Legal and contract counting often requires knowing which convention applies.

What is the difference between calendar days and business days?

Calendar days count every day of the week. Business days exclude weekends (Saturday and Sunday) and, depending on the country selected, national public holidays. The same date range can produce significantly different counts: a 30-day period typically contains 20–22 business days, and the exact number depends on which weekends and holidays fall within it.

What is the 1,000-day milestone?

1,000 days is approximately 2 years and 9 months from any start date. It has become a popular milestone celebrated by couples, sobriety programs, and long-term personal projects. Enter your start date and the calculator automatically shows the exact calendar date when the 1,000-day mark falls, alongside the 100-day, 500-day, 1-year, 2-year, and 5-year milestones.

How many business days are in a month?

On average, a month contains 20–23 business days, depending on the number of weekdays and national holidays in that month. A month with no holidays and a standard Monday–Friday structure has 21–23 working days. Use this calculator with specific start and end dates for an exact count that accounts for every holiday in that exact period.

Does the business days calculator support countries other than the US?

Yes — the calculator includes national holiday calendars for 7 countries: Brazil, United States, Spain, Germany, France, Italy, and Portugal. Select the country from the dropdown before calculating. For Brazil, all 12 national holidays defined by federal law are included, including the moveable holidays (Carnival, Good Friday, Corpus Christi) calculated per year.

Resources

• Time and Date — Date Duration Calculator — the most established online date calculator, useful as a cross-reference for complex date ranges.
• Wikipedia — Business Day — overview of how business days are defined across different legal and financial contexts worldwide.