Blog · July 1, 2026
Share of voice in SEO: definition, formula, and a worked example
Share of voice (SOV) in SEO is the percentage of available search visibility your site captures across a defined keyword set, weighted by each keyword's search volume and the expected click-through rate of your position. One number for a whole portfolio.
If rankings are the raw data, share of voice is the summary a leadership team can actually use. Here is the formula, a worked example, and why boards keep asking for it.
Why single positions are a bad executive metric
"We rank #3 for our main keyword" hides more than it reveals. It says nothing about the other 400 keywords, it weights a 100-searches-per-month term the same as a 10,000-searches term, and it ignores the fact that position 3 and position 8 get wildly different shares of clicks. A portfolio can look stable position-by-position while its real visibility quietly erodes on the highest-volume terms.
The share of voice formula
For each keyword in the set, estimate the clicks your position captures, then divide by the clicks available if you held #1 everywhere:
SOV = Σ (volume × CTR at your position) / Σ (volume × CTR at position 1)
CTR-by-position curves come from published click studies; the exact figures vary by study and SERP layout, but the shape is always the same: position 1 takes a large multiple of position 5, and page two takes almost nothing. If you are not in the top 10, your contribution for that keyword rounds to zero. Competitor SOV is computed the same way with their positions, which is what makes it a market-share metric: everyone's shares of the same keyword set sum to a comparable picture.
A worked example
A hypothetical, clearly illustrative portfolio of four keywords. Assume an illustrative CTR curve of 30% for #1, 15% for #3, 7% for #5, and 2% for #9 (rounded, for the sake of the arithmetic only):
Swipe sideways for the full table →
| Keyword (example) | Volume/mo | Your pos. | Your clicks | Max at #1 |
|---|---|---|---|---|
| keyword A | 10,000 | 3 | 1,500 | 3,000 |
| keyword B | 4,000 | 1 | 1,200 | 1,200 |
| keyword C | 2,000 | 5 | 140 | 600 |
| keyword D | 500 | 9 | 10 | 150 |
| Total | 16,500 | 2,850 | 4,950 |
Share of voice: 2,850 / 4,950 = 57.6%. Notice what the single positions hid: keyword B is a #1, which sounds like victory, but keyword A at #3 matters more to the total because of its volume. Losing three positions on keyword A would cost more visibility than losing keyword B entirely. SOV makes that trade-off arithmetic instead of argument.
Absolute vs relative share of voice
The formula above yields absolute SOV: your share of everything available, where 100% means ranking #1 for every keyword in the set. Some teams prefer relative SOV: your estimated clicks divided by the combined estimated clicks of a named competitor group, so the group always sums to 100%. Absolute answers "how much of the market do we hold"; relative answers "are we winning against these five companies". Relative is often the better boardroom framing, because a rising absolute number can hide a competitor rising faster. Pick one, define it in a footnote once, and never switch silently.
Three pitfalls that quietly corrupt the metric
- Changing the keyword set mid-stream. Add 200 keywords in March and your SOV "drops" in March. Version the set: when it changes, restate history or draw a line on the chart.
- Leaving branded terms in. You rank #1 for your own brand and competitors rank #1 for theirs. Branded queries inflate everyone's number while saying nothing about competition. Compute SOV on non-branded terms, or report both separately.
- Forgetting the SERP has changed. Ads, map packs, and AI answers eat clicks before position 1 gets any. The classic CTR curve overstates everyone's visibility on those queries. Consistency still saves the trend line, but do not present SOV points as literal click counts.
Why boards prefer it
A board deck has room for one SEO number, and "SOV moved from 22% to 31% this quarter while competitor X fell to 25%" is a market-share statement executives already know how to read. It survives keyword-set growth (positions on 500 keywords cannot be eyeballed, one percentage can), it exposes portfolio-level erosion early, and it frames SEO spend against competitors rather than against last month's rank wobble. This is the portfolio-wide view that enterprise rank tracking teams report on, with the share-of-voice trend as the headline chart.
How to start measuring it
You need three inputs: a defined keyword set (see how many keywords you should track), search volumes, and daily positions for you and your competitors. The positions are the part you cannot get manually at portfolio scale, which is where a rank tracker comes in. Serpstracker, currently in early access, tracks the daily positions and competitor columns that a share-of-voice calculation is built on, and its SEO ranking reports are designed to be forwarded upward without translation.
Define the set once, keep the CTR curve consistent, and trend the number monthly. Consistency matters more than the exact curve you pick: SOV is a compass, not a revenue forecast. Treat the direction as the signal, the decimal places as noise, and the competitor lines on the same chart as the story worth telling.