How is share of voice calculated?

Share of voice is a brand's marketing presence divided by the total presence of all competitors in the category, expressed as a percentage. It was traditionally based on advertising spend, but is now often measured across organic and earned channels too, such as share of search, media coverage, and social conversation.

Does share of voice really predict market share?

Research associated with John Philip Jones and later Les Binet and Peter Field found a consistent directional link: brands whose share of voice exceeds their share of market tend to gain share, and those below tend to lose it. The gap is called excess share of voice, or ESOV. It is a tendency across many cases, not a guarantee for any single brand, and it depends on the quality of the marketing.

Should I track share of market or share of voice?

Both, because they answer different questions. Share of market tells you your current competitive position from past results, while share of voice signals momentum and helps forecast where your share is heading. For a growth strategy, watching the gap between them is especially useful.

Share of market vs share of voice: two numbers, one story

Glossary · Glossary & Definitions · 4 min read · last verified 2026-07-21

Reviewed before publication Editorial board Independent commercial review

In shortShare of market is a brand's portion of actual category sales, while share of voice is its portion of total marketing presence; market share reflects results and share of voice tends to lead future change.

Share of market and share of voice are two different metrics that answer two different questions: share of market is a brand's portion of actual sales in its category, while share of voice is a brand's portion of the total marketing presence — advertising, media coverage, search, and conversation — in that same category. One measures the result a brand has already achieved; the other measures the attention it is currently commanding.

Share of market vs share of voice at a glance

Share of market (SOM): a brand's sales as a percentage of total category sales. Measures outcomes.
Share of voice (SOV): a brand's marketing presence as a percentage of total category presence. Measures attention.
SOM is lagging: it reflects buying decisions that have already happened.
SOV is leading: it tends to move before market share does.
Together they diagnose momentum: the gap between them signals whether a brand is likely to gain or lose share.

What share of market measures

Share of market is the share of category sales a brand holds, calculated as the brand's sales divided by the total sales of all competitors in the category, expressed as a percentage. It can be measured in revenue or in units, and the choice matters: a premium brand may hold a high revenue share but a smaller unit share, while a value brand may show the reverse.

Share of market is an outcome metric. It tells a company where it stands today as a result of everything that has already happened — product, pricing, distribution, and demand. Because it is a result, it is most useful for understanding position and less useful, on its own, for predicting the future. Defining the category boundary correctly is essential; a share number only means something relative to a clearly and consistently defined market. The honest market-sizing playbook and what SAM and SOM mean both bear on how that denominator is set.

What share of voice measures

Share of voice is the share of total category marketing presence a brand commands, calculated as the brand's presence divided by the combined presence of all competitors. Historically the metric was based on advertising spend — a brand's ad spend as a share of total category ad spend. Today it is measured more broadly to include organic and earned presence: share of search, share of media coverage, share of social conversation, and share of relevant keywords.

Share of voice is an input-and-attention metric. It approximates how much of the category's mindshare a brand is capturing right now, ahead of the sales those impressions may eventually produce. That forward-looking quality is what makes it valuable alongside share of market.

How they relate

The relationship between the two is one of the more durable findings in marketing. A long line of research — associated with analysts such as John Philip Jones and later Les Binet and Peter Field — describes it through the idea of "excess share of voice," or ESOV: the gap between a brand's share of voice and its share of market.

The established pattern is directional, not a precise formula:

When a brand's share of voice exceeds its share of market (positive ESOV), it tends to gain market share over time.
When a brand's share of voice is below its share of market (negative ESOV), it tends to lose share.
Brands that sustain a share of voice roughly in line with their market share tend to hold steady.

This is why share of voice is treated as a leading indicator: today's investment in attention tends to show up as tomorrow's movement in sales. The effect is a tendency across many cases, not a guarantee in any single one, and it depends on the quality of the marketing, not just its volume.

Which to track when

Both metrics belong on the same dashboard, because each is incomplete without the other. Share of market tells a brand where it is; share of voice helps it anticipate where it is heading.

Track share of market to understand current competitive position, judge the results of past strategy, and set realistic targets.
Track share of voice to gauge momentum, spot rivals investing ahead of their current position, and forecast likely share shifts.
Track the gap (ESOV) when the goal is growth: a brand aiming to gain share generally needs a share of voice above its share of market, sustained long enough for buying to catch up.
Watch both together to separate healthy growth from overreach — rising voice with flat market share may mean spend is inefficient, while rising market share with falling voice may signal a lead that is not being defended.

For a challenger deciding how hard to invest in attention, the two numbers also inform positioning and entry strategy — see how to enter a crowded market and price positioning. The practical takeaway is simple: measure the sales you have with share of market, measure the attention that predicts your next move with share of voice, and manage the distance between them.