The request
From Olivia Grant, E-commerce Manager
“My weekly trading call wants momentum, not annual totals: for each month of 2025, did sales go up or down compared with the month before, in percent? January should compare with December 2024, not show a blank.”
Your goal
The matrix has 'Date'[Year Month] on its rows and a 'Date'[Year] slicer on 2025. Write two measures: Sales PM (Sales of the previous month, with CALCULATE and DATEADD('Date'[Date], -1, MONTH)), then Sales MoM % = (Sales − Sales PM) ÷ Sales PM with DIVIDE. The last measure is checked.
- Fill
[Sales MoM %]on every row of the visualnot done yet - The Total row right toonot done yet
Your measure
- Visual
- A matrix: rows = 'Date'[Year Month]; values = [Sales], [Sales MoM %]
- Slicers
- 'Date'[Year] = 2025
- Measures in the report
Sales = CALCULATE(SUM(order_items[line_total]), orders[status] = "completed")
Data pane: tables and columns
- order_items order_item_id, order_id, product_id, quantity, unit_price, discount_pct, line_total
- orders order_id, customer_id, order_date, status, channel, shipping_fee, coupon_code
- products product_id, name, category, subcategory, unit_price, unit_cost, launched_on, is_active
- customers customer_id, first_name, last_name, email, city, state, signup_date, segment, referral_source
- returns return_id, order_item_id, returned_on, reason, refund_amount
- Date Date, Year, Quarter, Month Number, Month, Year Month, Year Quarter, Day, Weekday Number, Weekday
Loading the editor…
Reference solution
| Year Month | Sales | Sales MoM % |
|---|---|---|
| 2025-01 | $150,571 | |
| 2025-02 | $99,903 | |
| 2025-03 | $166,787 | |
| 2025-04 | $189,734 | |
| 2025-05 | $206,469 | |
| 2025-06 | $213,062 | |
| 2025-07 | $191,967 | |
| 2025-08 | $182,987 | |
| 2025-09 | $143,379 | |
| 2025-10 | $174,599 | |
| 2025-11 | $292,364 | |
| 2025-12 | $288,346 | |
| Total | $2,300,170 |
Mote checks your result
Press Check. Mote fills in your answer and compares it with what the report needs.
What Olivia gets, and why
The lesson
Year over year removes seasonality; month over month (MoM) shows momentum. A trading team looks at both: is this month better than the same month last year, and is it better than last month?
What you are working in
This page runs a practice DAX engine built for this site. It evaluates your last measure for each
month of 2025 and the Total row, and checks every cell. In Power BI Desktop: create each measure
with Home → New measure, format the second one as a percentage, and put
'Date'[Year Month] on the matrix rows.
DATEADD shifts dates by any interval
Sales PM = CALCULATE([Sales], DATEADD('Date'[Date], -1, MONTH))DATEADD(dates, number, interval) takes the visible dates and moves each one by number units of
interval (DAY, MONTH, QUARTER or YEAR). Negative goes back in time. For the row 2025-03:
- visible dates: March 1–31, 2025
- shifted: February 1–28, 2025 (a month-end day maps to the end of the shorter month)
[Sales]evaluated on those dates: February’s sales
DATEADD('Date'[Date], -1, YEAR) is the same as SAMEPERIODLASTYEAR, and -1, QUARTER gives the
previous quarter. One function covers every shift.
Measures that use measures
Sales MoM % = DIVIDE([Sales] - [Sales PM], [Sales PM])Writing Sales PM as its own measure, instead of a variable, makes it reusable: it can sit in the
matrix next to Sales, feed a tooltip, or be checked on its own. Variables are best for values only
one measure needs.
January and the Year slicer
The 2025-01 row has two filters on the calendar: Year = 2025 and Year Month = 2025-01. DATEADD produces December 2024, outside the slicer’s year. CALCULATE still sees it, because a filter on the marked Date table’s date column replaces every other filter on that table. So January compares with December 2024, as Olivia asked: down 48.2% after the holiday peak.
DATEADD or PREVIOUSMONTH?
PREVIOUSMONTH('Date'[Date]) returns the whole month before the first visible date. On a single
month it equals DATEADD by −1 month. On the Total row (all of 2025) it returns December 2024 only,
while DATEADD shifts the whole year back a month. DATEADD keeps the period’s length, which is
usually what a comparison needs.
Common mistakes
- A hard-coded month.
'Date'[Month Number] = MONTH(TODAY()) - 1breaks in January and ignores the row. - Comparing months of different length. February has three fewer days than March; part of March’s 66.9% jump is the calendar. For fair momentum, compare average daily sales or weeks.
- Reading MoM as trend. Month-over-month swings with seasons. Look at YoY next to it before calling a decline.
Lantern lit!
Practised: dateaddprevious monthmomdividetime intelligence
- Solved
- No hints
- First run