The P/E ratio adjusted for earnings growth.
Formula: PEG = P/E ÷ (annual EPS growth × 100) e.g. P/E 30, growth 0.15 → 30 ÷ 15 = 2.0
How to read it: < 1 = cheap relative to growth (Lynch's rule) · 1–1.5 = fairly valued · > 1.5 = expensive relative to growth. Enter growth as a decimal (0.15 = 15 %). PEG is not meaningful for negative earnings or zero/negative growth, so the function returns null.
Popularized by Peter Lynch, the PEG ratio improves on the P/E ratio by factoring in the expected growth rate.