What is year-over-year (YoY) growth?
Definition
Year-over-year (YoY) growth compares a metric in one period with the same period a year earlier, shown as a percentage change.
Why it matters
YoY removes seasonal swings, so you can see real growth instead of normal ups and downs.
How to do it
- Pick a metric and period, such as reach in October.
- Take this year's value minus last year's value.
- Divide by last year's value and multiply by 100.
Example
Reach was 20,000 last October and 26,000 this October: (26,000 − 20,000) ÷ 20,000 × 100 = 30% YoY growth.
YoY vs. month-over-month
Month-over-month shows short-term change but mixes in seasonality. YoY compares like with like.
FAQ
What if I don't have a full year of data?
Use month-over-month for now, and switch to YoY once you have a year of history.