ƒCalculatorFree
LifestyleVerified logic

Day Counter

Count calendar days, weekdays, weekends, and entered holidays between dates, or add business days to a date.

Day Counter Inputs

Enter comma-separated ISO dates such as 2026-01-19, 2026-12-25.

Count from a date

Results computed instantly — your data never leaves your device.

Day Counter Results

Real-Time

Calendar days

30

Weekdays

22

Weekend days

8

Business days

22

Monday–Friday, excluding entered holidays.

Offset date

2026-01-16

Entered holidays

0

100% Client-SidePrivate & Secure

How to Use the Day Counter

  1. 1

    Enter the start date and end date for the interval.

  2. 2

    Choose whether the end date should be included.

  3. 3

    Optionally list holiday dates in ISO format when interpreting business days.

  4. 4

    Review calendar days, weekdays, weekends, business days, and the offset-date result.

Formula & Mathematical Basis

Calendar days = included date count; business days = weekdays − listed holidays that fall on weekdays.

Variable Key

start/end

The interval endpoints at UTC midnight

includeEnd

Whether the final date is part of the interval

holiday

A listed date excluded from the business-day count

📝 The calculator treats Saturday and Sunday as weekends, counts the start date, and includes the end date only when selected. It does not automatically know country-specific public holidays.

Step-by-Step Examples

1

Count a project interval

Scenario: Compare January 1 through January 31 with the end date excluded.

  1. 1.Enter both ISO dates.
  2. 2.Leave Include the end date unchecked.
  3. 3.Review total calendar days and weekday/weekend split.
  4. 4.Add holiday dates only when they should be excluded from business days.
✅ The interval count follows the selected endpoint rule and shows the business-day estimate separately.

Practical Use Cases

  • Estimate working days remaining on a project.
  • Count days between events or deadlines.
  • Add or subtract calendar or business days from a known date.

Common Pitfalls

  • Forgetting that excluding the end date changes the total by one day.
  • Assuming all public holidays are automatically included.
  • Mixing a calendar-day offset with a business-day offset.

Frequently Asked Questions

Are weekends removed from calendar days?

No. Calendar days and business days are shown separately.

Does the tool know my country’s holidays?

No. Enter the holiday dates relevant to your calendar.

How does business-day offset work?

It moves forward or backward one date at a time and decrements the remaining count only on weekdays not listed as holidays.

Math & Everyday Utility Calculators

Solve common math, conversion, time, construction, science, and practical planning problems in the browser.