1. What Is This Calculator?

This calculator determines what day of the week it will be after a specified number of hours from a given starting day. It's useful for planning events, medication schedules, or any time-sensitive activities.

2. How Does It Work?

The calculator uses modular arithmetic to determine the future day:

Where:

• Start Day Index — 0 (Sunday) to 6 (Saturday)
• \(\lfloor x \rfloor\) — Floor function (greatest integer less than or equal to x)
• \(\mod 7\) — Remainder after division by 7 (for 7 days of the week)

3. Practical Applications

Details: Useful for calculating delivery dates, medication schedules, work shifts, or planning events that span multiple days.

4. Using the Calculator

Tips: Select the starting day and enter the number of hours. The calculator will show the resulting day and any remaining hours beyond full days.

5. Frequently Asked Questions (FAQ)

Q1: Does this account for daylight saving time?
A: No, this is a simple day-of-week calculator that doesn't consider time zones or daylight saving changes.

Q2: What if I need to calculate across weeks?
A: The calculator automatically wraps around to the next week(s) as needed.

Q3: Can I calculate minutes or seconds?
A: This version only calculates whole hours. For more precision, convert minutes to fractional hours.

Q4: What's the maximum number of hours I can enter?
A: There's no strict limit, but extremely large values may cause display issues.

Q5: Does this work for dates in the past?
A: Yes, you can enter negative hours to calculate days in the past.