Week Calculator
Calculate the exact number of weeks and days between two dates with ISO 8601 week numbers
Calculate Weeks Between Dates
Date from which you would like to count weeks
Date until which you would like to count weeks
By default, the starting day is not included in the counting
Quick Calculation Guide
Step 1: Count the days between the two dates
Step 2: Divide the number by 7
Step 3: Round down to get weeks, remainder is extra days
Example: 23 days ÷ 7 = 3 weeks + 2 days
Example Calculation
Project Timeline Example
Start Date: January 1, 2024 (Monday)
End Date: March 15, 2024 (Friday)
Total Days: 74 days
ISO Week Start: 2024-W01
ISO Week End: 2024-W11
Calculation
74 days ÷ 7 = 10 weeks + 4 days
Result: 10 weeks, 4 days
Duration: 2 months, 2 weeks, 4 days
Week Numbering Standards
ISO 8601 Standard
Monday is first day, Week 1 contains January 4th
US Standard
Sunday is first day, Week 1 contains January 1st
Middle East
Saturday is first day of the week
Week Facts
A year has 52 weeks plus 1-2 extra days
Leap years have 52 weeks + 2 days (366 days)
Normal years have 52 weeks + 1 day (365 days)
Some years have 53 ISO weeks
Understanding Week Calculations
How Week Counting Works
Week calculation involves determining the number of complete 7-day periods between two dates. The result shows both full weeks and any remaining days that don't form a complete week.
ISO 8601 Week Numbering
- •Monday is considered the first day of the week
- •Week 1 is the week containing January 4th
- •Week numbers range from 1 to 53
- •Thursday determines which year the week belongs to
Common Use Cases
- 📊Project Planning: Calculate project duration in weeks
- 💼Payroll: Calculate pay periods and work weeks
- 📚Education: Academic semester and term planning
- 🏥Medical: Treatment schedules and gestation periods
Tip: Use the "include starting date" option when counting inclusive periods, such as vacation days or project timelines where the start date is part of the duration.
Calculation Formula
Total Days = (End Date - Start Date) + (Include Start ? 1 : 0)
Weeks = Floor(Total Days ÷ 7)
Remaining Days = Total Days mod 7