Weeks Between Dates Calculator

The weeks between dates calculator helps you find the exact number of weeks from one date to another. It is free. It is instant. No manual math needed. You pick a start date. You pick an end date. The tool shows you the total number of full weeks plus any remaining days.

Calculate Weeks

How to use this calculator

Using this tool is simple. Follow these three steps.

Step 1: Enter your start date using the date picker.

Step 2: Enter your end date.

Step 3: Click Calculate. Your result appears instantly.

The result will show the total full weeks between the two dates, the remaining days after the full weeks, and the total number of days between the dates. You can use dates from the past or the future. The tool works both ways.

How to calculate weeks between two dates manually

You may not always have access to a calculator. Knowing the manual method is useful.

Step 1: Find the total number of days between the two dates. Count every day from the start date to the end date. Remember that different months have different day counts: January 31, February 28 (29 in a leap year), March 31, April 30, May 31, June 30, July 31, August 31, September 30, October 31, November 30, December 31.

Step 2: Divide the total days by 7. There are 7 days in one week.

Step 3: Round down to find full weeks. The whole number is your total full weeks. The leftover is your remaining days.

Example: Weeks between March 1 and June 15: 30 + 30 + 31 + 15 = 106 days. 106 divided by 7 = 15 full weeks and 1 remaining day.

The formula: Weeks = Total Days / 7 (round down) and Remaining Days = Total Days - (Weeks x 7)

Common uses for a weeks between dates calculator

Pregnancy tracking

Pregnancy is measured in weeks, not months. Doctors track development on a week-by-week basis. Enter the date of your last menstrual period as the start date, and the calculator tells you exactly how many weeks pregnant you are today. A full-term pregnancy lasts around 40 weeks.

Project management and work deadlines

Project timelines are often set in weeks. Sprints in Agile development usually last one to four weeks. Use the calculator to find out how many weeks remain between your project start date and your delivery deadline, then divide your tasks into weekly milestones.

School and academic planning

A typical school year in the US runs for about 36 weeks. A university semester is usually 15 to 16 weeks. Students use this tool to plan study schedules. Teachers use it to map out lesson plans. Parents use it to track holidays and breaks.

Legal and contract timelines

Legal documents often set deadlines in weeks. Notice periods, appeal windows, and payment terms may all be expressed as a number of weeks from a specific date. The calculator helps you find the exact deadline date.

Event planning and countdowns

Planning a wedding, a birthday, a product launch, or a trip? The weeks calculator tells you exactly how much time you have. Counting weeks gives you a cleaner view than counting days and helps you set weekly preparation goals.

Health and fitness goals

Many fitness programs run for a set number of weeks. A 12-week training plan or a 6-week diet challenge requires you to track progress by week. Enter your start date and program end date to see exactly where you stand.

Financial and payroll planning

Some salaries, rents, or loan repayments are set on a weekly basis. Knowing the exact number of weeks in a period helps with accurate calculations.

Weeks between dates in Excel and Google Sheets

If you work with spreadsheets, you can also calculate weeks between dates without an online tool.

Using Excel

In Excel, use this formula to get the number of full weeks between the date in cell A2 (start) and cell B2 (end):

=INT((B2-A2)/7)

To also show remaining days:

=INT((B2-A2)/7) & " weeks, " & MOD((B2-A2),7) & " days"

Using Google Sheets

Google Sheets uses the same logic. Enter your start date in A2 and end date in B2, then use:

=INT((B2-A2)/7)

Both programs handle leap years automatically when dates are entered correctly.

Weeks in a year

A standard year has 365 days. 365 divided by 7 equals 52 weeks and 1 extra day.

A leap year has 366 days. 366 divided by 7 equals 52 weeks and 2 extra days.

This is why the calendar shifts slightly from one year to the next, and why a specific date does not always fall on the same weekday each year.

What is the ISO week standard?

ISO 8601 is an international standard for date and time that defines how weeks are numbered globally.

Under this standard: a week always starts on Monday, the first week of the year is the week that contains the first Thursday of January, and weeks are numbered from 01 to 52 or 53.

This standard is used in business planning, international logistics, and project management tools. Some countries start the week on Sunday instead of Monday. The US, Canada, and several others follow this convention.

Tips for accurate date calculations

Check whether the start date is included. Some calculators include the start date in the count. Others do not. Our calculator does not count the start date as a separate day. It counts from the day after your start date to your end date.

Account for leap years. If your date range includes February 29, the total day count changes. Our calculator handles this automatically.

Be clear on time zones. If you are calculating across international dates and time zones, the day count can sometimes differ by one. Use the local date relevant to your purpose.

Double-check long date ranges. If you are calculating across multiple years, manually verify the result using a second method to confirm accuracy.

Real-world examples

Jan 1 to Dec 31, 2026

Full calendar year

52 weeks

364 days

Australian financial year (FY2026)

1 Jul – 30 Jun

52 weeks

364 days

AU School Term 1 2026

28 Jan – 3 Apr

9 weeks

65 days

Typical 12-week fitness program

e.g. Apr 1 – Jun 24

12 weeks

84 days

Frequently Asked Questions

How do I calculate the number of weeks between two dates?

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Count the total number of days between your start and end date. Then divide that number by 7. The result gives you the number of full weeks. Any leftover number is the remaining days. For example, 50 days equals 7 full weeks and 1 remaining day.

Does the calculator count the start date or the end date?

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Our calculator does not include the start date in the count. It starts counting from the day after your start date. The end date is included. This is the standard method used in most professional and legal contexts.

Can I calculate weeks between dates that already passed?

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Yes. Enter any two past dates and the calculator will tell you how many weeks fell between them. This works for historical research, anniversary calculations, or reviewing past timelines.

How many weeks are between two dates one year apart?

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If the date range does not cross a leap year, the answer is 52 weeks and 1 day. If it crosses a leap year and includes February 29, the answer is 52 weeks and 2 days.

How many weeks is 3 months?

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Three months is roughly 13 weeks. However, this depends on which months you are counting. Three months with 31 days each would equal about 13 weeks and 2 days. The exact count varies based on the actual calendar months.

How many weeks is 6 months?

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Six months is approximately 26 weeks. However, the exact number depends on which six months you choose. Some months have 30 days and some have 31, so the total will vary slightly.

How do I calculate how many weeks pregnant I am?

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Enter the first day of your last menstrual period as the start date. Enter today as the end date. The result tells you exactly how many weeks and days pregnant you are.

Does the calculator handle leap years?

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Yes. The calculator automatically accounts for leap years. If your date range includes February 29, that extra day is included in the total day count and reflected in the week calculation.

Can I use this to calculate business weeks only?

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The standard calculator counts all calendar days, including weekends and public holidays. If you need business days only, you would need to subtract weekends and any holidays from the total day count. Some spreadsheet tools offer a NETWORKDAYS function for this purpose.

How many weeks are in a school year?

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A typical school year in the United States runs for about 36 weeks. This equals 180 school days. The exact number varies by school district, state, and country. From September 2 to June 5 is approximately 39 weeks in total, though not all of those are active school weeks.

Why does my calendar show a different week number than what I expect?

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This usually comes down to the ISO 8601 standard versus local conventions. ISO weeks start on Monday, while some countries start on Sunday. The first week of the year is also defined differently across standards. Make sure you and the other party are using the same week numbering system.

Is there a way to count only weekdays between two dates?

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Yes, but not with a standard weeks calculator. In Excel, you can use the NETWORKDAYS function. In Google Sheets, the same function is available. It counts all days between two dates while excluding Saturdays, Sundays, and any holidays you specify.

How many weeks until Christmas from today?

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This depends on the current date. Enter today as the start date and December 25 as the end date. The calculator will show you the exact number of weeks and days until Christmas.

What is the difference between calendar weeks and work weeks?

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A calendar week includes all 7 days from Monday to Sunday. A work week typically covers Monday to Friday, which is 5 days. When people count weeks for payroll, timesheets, or projects, they may mean work weeks rather than full calendar weeks.

Can I use this calculator for countdown timers?

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Yes. Enter today as the start date and your target event as the end date. The result gives you a weekly countdown. Many people use this for weddings, exams, sports events, and travel.

What if my start date is after my end date?

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If you enter the start date after the end date, the calculator will still return a result. The week count will reflect the period between the two dates. Some calculators may return a negative number to indicate the end date is in the past relative to the start.

How many weeks is 100 days?

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100 days equals 14 weeks and 2 remaining days. This is because 14 multiplied by 7 equals 98, leaving 2 extra days.

How many weeks between two dates if I include both the start and end date?

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If you want to include both dates, add 1 to your total day count before dividing by 7. For example, if there are 91 days between your dates and you want to count both endpoints, use 92 days instead. That gives you 13 weeks and 1 day.

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