This **week calculator** retrieves week start and end dates based on a given week or calculates the week number for the chosen year. Below the form you can read more about this subject and also discover an example calculation.

## How does this week calculator work?

This time tool can help you whenever you need to find either the week number based on a certain date or the week dates based on a week number. Depending on what week calculation you would like to perform you need to input only the required data within the *week calculator* fields. The tool then checks the calendar and returns the following:

- If you calculate the week dates based on week number you will be returned the start and end date of that given time.
- If you compute based on a date, be it a start, end or middle day, you will receive the week number.

## Example calculation

- Using the week number tab:

Let’s say we would like to know the dates for the week no. 17 from 2005. The result says the start date was on April 18, 2005 while the end date was on April 24, 2005.

- Using the date tab:

Let’s discover which week included the June 18 2001 date. The result says this day belongs to week 25 of that year.

## How many weeks per year?

Do you know exactly how many weeks there are in a year and what happens if the New Year doesn’t start straight from a Monday? A year has either 365 days or 366 days if it’s a leap year. If it were to divide this by 7 it would result 52 and a rest of 1 day or 2 days. Therefore there are 52 weeks in a year.

For common years, they end on the same day of the week as they started. But the leap years have a one day delay as shown in the table below:

Leap year | |

Starts on… | Ends on… |

Monday | Tuesday |

Tuesday | Wednesday |

Wednesday | Thursday |

Thursday | Friday |

Friday | Saturday |

Saturday | Sunday |

Sunday | Monday |