Share of voice (SOV) is your brand’s portion of all the visibility in a category: classically, your advertising spend divided by total category advertising spend. Today teams also measure it in search impressions, social mentions, press coverage and AI answers. The comparison that matters is SOV against your share of market.
What is share of voice?
In the advertising-effectiveness research of Les Binet and Peter Field, published by the UK’s Institute of Practitioners in Advertising and drawing on its databank of more than 1,200 effectiveness case studies, share of voice is ad spend divided by category ad spend, and the pattern is consistent: if share of voice exceeds share of market, sales tend to grow; if it is similar, sales tend to hold; if it is smaller, sales tend to shrink.1Source 1 · Westwood One (summarizing Binet & Field, IPA), 2018A Simple Math Equation Can Predict If Sales Grow, Fall, Or Remain Stablewestwoodone.com
SOV=Your brand’s visibility ÷ Total category visibility; ESOV = SOV − Share of market
- Visibility
- Ad spend (classic), impressions, mentions, citations, depending on the channel
- Share of market
- Your sales ÷ total category sales
Which kinds of share of voice can you measure?
| Channel | Numerator | Denominator |
|---|---|---|
| Advertising | Your ad spend | Category ad spend (estimated) |
| Paid search | Your impressions | Total eligible impressions (impression share) |
| Organic search | Estimated clicks on tracked keywords | Clicks for all tracked competitors |
| Social & press | Mentions of your brand | Mentions of all tracked brands |
| AI answers | Answers citing your domain | Answers across tracked prompts |
Paid search has a built-in version: Google Ads impression share is your impressions divided by the total impressions your ads were eligible to receive.2Source 2 · Google Ads HelpAbout impression sharesupport.google.com For AI answer engines, see generative engine optimization.
Worked example
A brand spends $2.0M on advertising in a category where competitors and the brand together spend $16.0M: SOV = 12.5%. Its market share is 10%, so ESOV = +2.5 points, a position Binet and Field’s data associates with growth. A rival with 20% market share and 15% SOV runs −5 points of ESOV and is, on that evidence, at risk of losing share. Illustrative numbers.
Common mistakes
- Changing the competitor set between reports, which moves SOV without any real change.
- Counting all mentions equally: a negative news cycle can spike social SOV.
- Treating SOV as causal. The relationship is an empirical pattern across many brands, not a guarantee for one.
How to track share of voice in Kimo
Kimo combines Semrush keyword visibility, Google Ads impression share, press coverage and social mentions into one competitor model with a fixed brand list. The Command center shows SOV by channel next to revenue, and the social media overview template breaks out social share.
Frequently asked questions
What is excess share of voice?
How do I estimate competitors’ ad spend?
Sources
2 references- A Simple Math Equation Can Predict If Sales Grow, Fall, Or Remain Stable (opens in a new tab)Westwood One (summarizing Binet & Field, IPA)2018westwoodone.com
SOV = ad spend ÷ category ad spend; SOV vs share of market and sales growth.
- About impression share (opens in a new tab)Google Ads Helpsupport.google.com
Impression share = impressions ÷ total eligible impressions.
External sources were accessed at the time of writing. Kimo product details, customers and figures in examples are illustrative unless a source is cited.
