Share of Voice vs Share of Market Calculator

How it works

SOV = your spend ÷ total category spend; ESOV = SOV − SOM; expected annual share change ≈ ESOV (pts) × 0.03–0.07 (leader → challenger); spend for a target SOV = target × competitor spend ÷ (1 − target)

Share of voice is a brand’s slice of the category’s advertising, and decades of IPA and Nielsen data show that brands whose share of voice exceeds their share of market tend to grow, while those that under-spend tend to shrink — the “excess share of voice” rule, with roughly half a point of market share gained per year for every ten points of ESOV (more for small brands, less for leaders, who can coast on existing salience). The relationship is a tendency across many brands, not a law; it assumes reasonably effective creative and a product people can buy. The arithmetic here sets the budget conversation: what SOV the current spend buys, how far it sits from market share, and what it would cost to buy a target voice if competitors stand still — which, of course, they rarely do.

Worked example

Spending $2.5 M in a category where competitors spend $12.2 M gives a 17.0% share of voice against a 14% market share: +3 points of ESOV, worth roughly +0.15 share points a year for an established brand. Reaching a 20% SOV would take about $3.05 M — $550 k more — if rivals hold steady.

Frequently asked questions