Calculating Previous Month’s Month-to-Date (MTD) Sales with DAX

Monitoring sales performance is important to any business, and knowing your sales versus the last month can be very useful. In this blog post, we will be discussing how to calculate the last month’s Month-to-Date (MTD) sales via Data Analysis Expressions (DAX) within Power BI or Excel.

What is Month-to-Date (MTD)?
Month-to-Date (MTD) is the time from the start of the current month to the current date. MTD sales for the last month are calculated so that businesses can compare their current performance with the same period last month.

The DAX Formula for Previous Month’s MTD Sales
To calculate the previous month’s MTD sales, we use the following DAX formula:

Previous_MTD_Sales = 
CALCULATE(
    SUM(Sales[SalesAmount]),
    DATESMTD(
        DATEADD(Date[Date], -1, MONTH)
    )
)

Let’s dissect this formula:

• CALCULATE: This function changes the context under which data is calculated. It enables us to filter and calculate within a context.
• SUM(Sales[SalesAmount]): This section of the formula totals the sales values in the Sales table.
• DATESMTD: This operation returns a table with a column of dates for the month-to-date.
• DATEADD(Date[Date], -1, MONTH): This operation moves the dates one month backward, hence returning the dates of the preceding month.

Step-by-Step Instructions

1. Make Sure You Have a Date Table: Ensure your data model has a date table with a continuous range of dates. This date table should be associated with your sales table.
2. Develop the Previous Month’s MTD Sales Measure:
   • Launch Power BI Desktop or Excel
   • Go to the Data or Model view
   • Choose the Sales table.
   • Click on “New Measure” and type in the previous month’s MTD sales formula given above.
3. Visualize the Previous Month’s MTD Sales:
   • Create a new report or dashboard.
   • Add a visual, like a card, table, or chart.
   • Drag the Previous_MTD_Sales measure to the visual to show the prior month’s MTD sales.

Benefits of Tracking Previous Month’s MTD Sales

• Performance Comparison: Comparing the MTD sales of the current month with the MTD sales of the last month will help you determine trends and patterns in your sales performance.
• Timely Adjustments: Knowing how your sales are doing relative to last month enables you to make timely adjustments to your operations and strategies.
• Informed Decision-Making: Monitoring last month’s MTD sales gives you important information that can guide your business decisions and enable you to meet your sales goals.

Conclusion
Calculating last month’s MTD sales with DAX is a great way to get insights into your business performance and make data-driven decisions. With the steps described in this blog post, you can easily apply this calculation in Power BI or Excel and begin comparing your sales performance month-to-month.

Leave your comments or questions below. Happy analyzing!