Weekday Calculator

The Weekday Calculator determines the day of the week for any given date, and provides contextual information about that date's position in the week, month, and calendar year. It answers questions like "What day of the week is July 4, 2026?", "Is September 15 a weekend?", "Which number Monday of the month is October 12?", and "How many days until the next Monday?"

The calculator uses JavaScript's built-in Date.getDay() method, which returns the ISO day of week (0=Sunday through 6=Saturday), and derives all other positional information from simple arithmetic on the day of month and week positions. It also lists all occurrences of the same weekday within the month, which is useful for recurring meeting scheduling and calendar planning.

Beyond the single-date lookup, this calculator shows how many days remain until the next Friday (or any upcoming weekend), how many days have passed since the last Monday, and the date's position as the nth weekday of its month — information essential for payroll schedules, meeting recurrences, and event planning.

The day of week is a fundamental calendar computation. The calculator uses the built-in Date API, but the underlying math follows Zeller's or Tomohiko Sakamoto's algorithm for any Gregorian date.

Many recurring events and floating holidays are defined as "the 2nd Tuesday of the month" or "the last Monday." The calculator determines the position by dividing the day of month by 7:

• Week of month: ceil(dayOfMonth / 7) — returns 1–5
• All same weekdays in month: Starting from day 1 + offset, list all occurrences of the target weekday within the month
• Is it the last occurrence? If weekOfMonth = 5 or (weekOfMonth = 4 and dayOfMonth + 7 > daysInMonth), then it is the last occurrence

This information is essential for recurring calendar events: US Thanksgiving is the 4th Thursday of November, UK Mother's Day is the 4th Sunday of Lent, and many payroll pay periods are tied to specific weekday occurrences.

1. Select a Date: Use the date picker to choose any date. The calculator defaults to today.
2. Read the Day of Week: The day name (Monday, Tuesday, etc.) is displayed prominently, along with whether it's a weekday or weekend.
3. Check Position Details: See which occurrence of this weekday it is within the month (1st, 2nd, 3rd, 4th, or 5th), how many days until the next weekend, and how many days since the last Monday.
4. View Month Occurrences: All dates in the same month that fall on the same weekday are listed.

Calendar automation systems need to resolve "nth weekday" rules into specific dates. HR systems that generate "2nd and 4th Friday" payroll dates, project management tools that create recurring sprint review meetings, and church scheduling systems that plan services on specific Sundays all require weekday position calculations. This calculator provides the manual reference for verifying automated results.

Legal and financial deadlines are often expressed as "the first Monday of March" or "the last business day of the quarter." Court filing deadlines, tax payment dates, and bond coupon payment dates may all be defined relative to a weekday occurrence within a month or quarter. A weekday calculator confirms the correct calendar date before important filings.

Event planning professionals use weekday calculators to check whether a proposed event date falls on a convenient day of the week. Booking a venue for "the second Saturday of October" requires knowing whether it falls on October 8, 14, or 15 depending on the year — this calculator answers that instantly.