YoY (Year-over-Year)

A comparison of a financial metric to the same period in the previous year.

What Is Year-over-Year (YoY)?

Year-over-Year (YoY) is a method of comparing a financial metric from one period to the same period in the previous year. For example, comparing Q1 2026 revenue to Q1 2025 revenue gives you the YoY revenue growth rate.

YoY Growth = ((Current Period - Same Period Last Year) ÷ Same Period Last Year) × 100

Why YoY Is the Standard

YoY comparison is preferred because it naturally accounts for seasonality. Retail companies always have stronger Q4 (holiday season) revenue. Comparing Q4 to Q3 would make it look like the business is booming, when really it's just seasonal. YoY compares Q4 to Q4, giving an apples-to-apples view.

Reading YoY Data

When analyzing earnings reports, investors focus on YoY growth rates for key metrics: revenue growth, EPS growth, margin expansion/contraction, and user/subscriber growth. Acceleration in YoY growth (e.g., from 15% YoY to 20% YoY) is a strong bullish signal, while deceleration is a warning sign.