How Do I Count Weeks Between Dates?
Counting weeks between two dates is straightforward once you know the method. Follow these steps:
- Count the total number of days between the two dates.
- Divide that number by 7.
- Round down to the nearest whole number — that is your full weeks count.
- The remainder (0–6) is the number of extra days beyond the full weeks.
Note: The starting day is not included in the count. For example, from Monday 1 Jan to Monday 8 Jan = 7 days = exactly 1 week.
How to Use the Week Calculator
Our week counter tool is simple to use:
- Start Date — The date from which you want to count weeks.
- End Date — The date until which you want to count weeks.
After entering both dates, the calculator instantly shows:
- Total full weeks between the dates.
- Remaining days beyond full weeks.
- Total number of days.
- Day of the week for each date.
- ISO 8601 week number (international standard, Monday-first).
- US/Canada week number (Sunday-first system).
- Whether each date falls in a leap year.
ISO 8601 Week Numbering Standard
Our calculator supports two week numbering systems:
ISO 8601 (International / Metric Standard)
Used in most of Europe, Australia, and international business:
- The first day of the week is Monday.
- Week 1 of a year is the week containing 4 January (or the first Thursday of the year).
- Week numbers range from 1 to 52 or 53.
- Week 1 may start in the last days of the previous year (e.g., Week 1 of 2025 starts on Monday, 30 December 2024).
US / Canada System (American Standard)
Used in the United States, Canada, China, and several other countries:
- The first day of the week is Sunday.
- Week 1 begins on January 1st of the year.
- Weeks are counted sequentially from January 1st.
FAQs
What is the first day of the week?
It depends on the country and convention. The ISO 8601 international standard (used widely in Europe and business) designates Monday as the first day. Many countries including the US, Canada, and China consider Sunday the first day, while some Middle Eastern countries begin with Saturday.
How many weeks are in a year?
A standard (non-leap) year has 365 days: 365 ÷ 7 = 52 weeks and 1 day. A leap year has 366 days: 366 ÷ 7 = 52 weeks and 2 days. This means no year has exactly 52 weeks — there is always 1 or 2 extra days.
Does a year have exactly 52 weeks?
No. Since 52 × 7 = 364, every year has at least 1 extra day. This is why some years have an ISO week 53 — that 53rd week covers the 365th day (and the 366th in leap years).
How many weeks are in a leap year?
A leap year has 366 days, which equals 52 weeks plus 2 extra days. Whether a given leap year gets ISO week 53 depends on which day January 1st falls on.
What is the difference between weeks between dates and weeks from a date?
This calculator counts full weeks between two specific dates. The start date is not counted — only the days after it up to (and including) the end date. This is the standard used in business, legal, and scheduling contexts.
💡 Related tools: If you need the number of days, try our Day Counter. For months between dates, see our Month Calculator.