Share of voice measures how much of a market's advertising belongs to one brand. If a category spends a hundred million dollars on ads and your brand accounts for twenty million, your share of voice is twenty percent.

Marketers compare share of voice to market share. Brands that spend above their market share tend to grow. Brands that underspend tend to shrink, though the relationship is not perfectly linear and depends on category dynamics.

Where share of voice applies

• Traditional media like television and print
• Digital channels and search
• Social media mentions and engagement
• Trade publications in B2B categories

The metric has limits. Spending more than competitors does not guarantee success if the creative is weak or the audience is wrong. It measures effort, not effectiveness.