Excess Share of Voice Calculator
Excess share of voice is the single best-evidenced lever in brand growth: spend a larger share of the category’s voice than your share of its sales, and you tend to grow. Enter two numbers to see your ESOV and what it is likely to buy you.
ESOV = your share of voice (your media spend as a percentage of the category’s total) minus your market share. The relationship comes from Les Binet and Peter Field’s IPA work: brands with positive ESOV tend to gain share, and the widely cited rule of thumb is that roughly 10 points of ESOV buys about 0.5 points of market-share growth per year. A positive ESOV sets you up to grow; a negative one usually means slow erosion.
Excess Share of Voice Calculator inputs and result
How to use this calculator
- Work out your share of voiceTake your category advertising spend and divide it by the total advertising spend of every brand competing in the category. Multiply by 100. This is your share of the conversation, not your share of sales.
- Enter your market shareUse your sales or revenue as a percentage of total category sales for the same period. Keep both numbers on the same scope — same market, same time window.
- Read your ESOVThe tool subtracts market share from share of voice. A positive number means you are out-shouting your size; a negative number means rivals are out-voicing you.
- Set the multiplier for your categoryThe IPA default is 0.5 points of growth per 10 points of ESOV. If your category or creative is unusually strong, nudge it up; if media converts weakly to share, nudge it down.
- Use the projection to planThe projected share growth is a directional planning figure for the year ahead. Pair it with a creative-quality check before you commit budget, then export the numbers for the plan.
RGM Expert Says
ESOV is the number we reach for when a client wants to argue brand budget on evidence rather than faith. The Binet & Field dataset is the closest thing our field has to a law of motion: brands that hold share of voice above market share tend to grow, and the gap predicts the rate. When a CFO asks ‘what does brand spend actually buy,’ this is the honest, sourced answer — a probabilistic tilt toward share gains, not a guaranteed return.
We are careful about two things when we use it. First, share of voice has to be measured against the real competitive set, including the disruptor nobody wants to count; an ESOV that looks positive against three legacy rivals can be deeply negative once a well-funded challenger is included. Second, the 0.5 multiplier is an average across many cases, not a constant. Excellent creative can lift the conversion of voice into share well above it, and weak creative can sink it below — so we treat the projection as a planning range, not a forecast.
The most common use we see is defensive. A brand cutting media in a downturn often shows a freshly negative ESOV, which is the early-warning sign of the share decline that arrives a year or two later. Putting that number in front of leadership reframes the budget conversation from ‘a cost to trim’ to ‘the price of holding position’ — which is usually the more accurate framing.
How it works
ESOV is a simple difference, and its predictive power comes from the historical relationship Binet & Field documented across hundreds of campaigns.
- Share of voice — your media spend as a percentage of total category media spend.
- Market share — your sales as a percentage of total category sales.
- Multiplier — points of annual share growth per 10 points of ESOV; the IPA default is about 0.5.
The ESOV-to-growth relationship is documented in Les Binet & Peter Field’s IPA work, summarized in Media in Focus and The Long and the Short of It. The 0.5 figure is an average across cases, not a fixed constant.
Why share of voice beats your size matters
Most budget fights treat advertising as a cost to minimize. The ESOV evidence reframes it as a position to defend. Across hundreds of IPA case studies, Les Binet and Peter Field found that brands sustaining a share of voice above their market share tended to grow, while those letting voice slip below their size tended to shrink. The gap — excess share of voice — is the lever, and the effect compounds over years, not weeks.
The trap is treating ESOV as a quick-win dial. It is a long-term mechanism: the share movement shows up gradually, which is precisely why under-funded brands rarely notice the erosion until it is well underway. That long lag is also why brands that cut media in a downturn often pay for it with lost share a year or two later, when the bill finally arrives.
ESOV is necessary but not sufficient. Money buys you the chance to be heard; creative quality and broad reach decide how much of that voice converts into memory and sales. Use this tool to size the opportunity, then hold the work to a high creative bar so each point of voice does more than the average.
How to read your ESOV
There is no single ‘good’ ESOV — it is relative to your size and ambition. The bands below translate the gap into the share trajectory it tends to imply.
| ESOV | What it tends to mean | Typical action |
|---|---|---|
| Strongly negative | Out-voiced by rivals; share erosion likely | Raise media weight or sharpen creative |
| Around zero | Spending in line with size; share roughly flat | Decide whether to defend or push |
| Positive (+5 to +10) | Set up for steady share gains | Sustain the gap; protect creative quality |
| Strongly positive (+15+) | Aggressive growth posture | Ensure spend is not outrunning effectiveness |
What the effectiveness research says
Brands that set their share of voice above their share of market tend to grow; the size of that excess share of voice predicts the rate of growth.
The long-term effects of advertising build slowly and are far larger than the short-term sales blips that get all the attention.