How To Find Seasonal Index Jun 2026

| Month | Seasonal Index | | --- | --- | | Oct | 90 | | Nov | 110 | | Dec | 140 | | Jan | 160 | | Feb | 150 | | Mar | 120 |

We must adjust them proportionally so the math remains balanced. how to find seasonal index

Overall average = (100 + 120 + ... + 200 + 110 + ...) / 24 = 130 | Month | Seasonal Index | | ---

In a perfect world, the sum of your seasonal indices should equal the number of periods in a year. For , the sum should be 4.0 . For monthly data , the sum should be 12.0 . For , the sum should be 4

Finding the seasonal index isn't just an academic exercise in statistics. It is a practical tool that transforms raw data into actionable business intelligence.

This result now aligns perfectly with the third period in your data set. Step 3: Find the Ratio of Actual Value to CMA

Gather your historical data and organize it into a table or spreadsheet with the following columns: