# Date.DaysInMonth

## What is the Date.DaysInMonth Function?

The Date.DaysInMonth function is used to calculate the number of days in a month for a given date. This can be useful for a variety of tasks, such as calculating the number of days between two dates or determining the number of working days in a month.

The function takes two arguments: a date, and an optional culture. The culture argument is used to specify the culture to be used for the calculation. If the culture argument is not specified, the default culture for the system is used.

## The M Code Behind Date.DaysInMonth

Behind the scenes, the Date.DaysInMonth function is actually implemented in M code. The M code for the function is as follows:

(Date as date, optional Culture as nullable text) as number =>

Date.EndOfMonth(Date.StartOfMonth(Date, Culture), Culture) – Date.StartOfMonth(Date, Culture) + 1

``` Let's break down the code and see how it works. The Date.EndOfMonth Function The first part of the code uses the Date.EndOfMonth function to determine the last day of the month for the given date. The Date.EndOfMonth function takes a date and an optional culture as arguments, and returns the last day of the month for the given date. The Date.StartOfMonth Function The second part of the code uses the Date.StartOfMonth function to determine the first day of the month for the given date. The Date.StartOfMonth function takes a date and an optional culture as arguments, and returns the first day of the month for the given date. Calculating the Number of Days Once we have the first and last days of the month, we can calculate the number of days in the month. To do this, we simply subtract the first day of the month from the last day of the month and add 1. In this article, we took a closer look at the M code behind the Power Query M function Date.DaysInMonth. We saw how the function is implemented using the Date.EndOfMonth and Date.StartOfMonth functions to calculate the number of days in a month for a given date. Understanding the M code behind functions like Date.DaysInMonth can be extremely helpful when working with Power Query, as it allows you to create more complex transformations and queries. Power Query and M Training Courses by G Com Solutions (0800 998 9248) Power Query and M Intensive Training Course £1,050.00 – £26,550.00 Select optionsContinue Loading Done Power Query and M Introduction £395.00 – £9,750.00 Select optionsContinue Loading Done Power Query and M Intermediate £395.00 – £9,750.00 Select optionsContinue Loading Done Power Query and M Advanced £395.00 – £9,750.00 Select optionsContinue Loading Done Upcoming Courses Contact Us Subject Your Name (required) Company/Organisation Email (required) Telephone Training Course(s) Power BI Intensive TrainingPower BI introduction Power BI IntermediatePower BI AdvancedDAXPower Query MPower BI CertificationPower BI AdministrationPower PlatformPower AutomatePower AppsOTHER Your Message Upload Example Document(s) (Zip multiple files) ```
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