Measurement & Decisioning · 22 August 2026 · 7 min read
Share of search: how to calculate it and use it in media planning
Share of search is a brand's proportion of branded search demand within a defined competitor set. Calculate it by dividing searches for your brand by searches for your brand plus the competing brands, using the same market, period, search engine and query rules for every brand.
Key takeaways
- The formula is simple; the hard part is defining a stable competitor set and equivalent branded queries.
- Use one consistent data source. Google Trends supplies a relative index, while keyword tools supply estimated volumes; neither should be mixed with the other in one calculation.
- Track the trend over time rather than overreacting to one month. Launches, news, seasonality and crises can all create temporary spikes.
- Share of search is a demand signal, not an SEO ranking metric, Google Ads impression share or proof that media caused the movement.
The share of search formula
For a fixed set of brands, share of search is calculated as your brand's branded searches / total branded searches for all brands in the set x 100. If your brand receives 2,400 searches and the complete competitor set receives 7,600, total category brand search is 10,000 and your share of search is 24%.
| Brand | Searches | Share of search |
|---|---|---|
| Your brand | 2,400 | 24% |
| Competitor A | 5,100 | 51% |
| Competitor B | 1,600 | 16% |
| Competitor C | 900 | 9% |
| Category total | 10,000 | 100% |
The percentage becomes useful when repeated with the same rules. A movement from 18% to 24% over six months suggests your brand is capturing a larger share of active category interest. It does not, on its own, explain why the movement happened or guarantee a corresponding change in sales.
Step 1: define the market and competitor set
Choose competitors from the buyer's real consideration set, not from an internal list of companies you admire. The set should be specific to a market and product category. A global parent brand may compete with different local brands in the UK, UAE and US, so a single worldwide denominator can hide the planning signal.
- Start with three to seven brands that repeatedly appear in customer research, sales conversations and search comparisons.
- Keep the set stable so a percentage change reflects demand, not a denominator that was quietly redefined.
- Document acquisitions, rebrands and major entrants. Backfill their history where possible or mark a series break.
- Create separate views where regional consideration sets genuinely differ rather than averaging incompatible markets.
Step 2: build equivalent branded-query sets
One brand may have a unique name while another shares a common word with a person, place or product. Counting only the exact company name can therefore favour the cleaner brand. Build a query set for each competitor that captures genuine brand demand and excludes obvious ambiguity.
| Include when relevant | Handle carefully | Usually exclude |
|---|---|---|
| Brand name and common spelling | Acronyms with several meanings | Generic non-brand category terms |
| Recognised misspellings | Founder or spokesperson names | Support queries unrelated to consideration |
| Major product or sub-brand names | Short names shared with places or people | Jobs, login and investor queries if the goal is buyer demand |
| Brand + category combinations | Temporary campaign slogans | Navigational queries created by internal staff |
Apply the same inclusion logic to every brand. If product names are counted for your brand, comparable product demand should be counted for competitors. Keep the raw query mapping beside the monthly calculation so another planner can audit changes.
Step 3: choose one data source
| Source | What it provides | Best use |
|---|---|---|
| Keyword research platform | Estimated monthly search volumes by term and market | A repeatable category table where all brands use one provider |
| Google Trends | A normalised 0-100 index for compared topics or terms | Directional trends, seasonality and regional movement |
| Google Search Console | Impressions and clicks for queries that surfaced your own site | Validating your brand-query set, not measuring competitor demand |
| First-party search or site data | On-site and navigational behaviour for your properties | Supporting diagnosis, not constructing the market denominator |
Google Trends values are indices, not raw search counts. Compare all brands under the same geography, period, category and search type, then calculate each brand's share of the combined index for that period. If a query is ambiguous, compare a Google Trends topic where an appropriate topic exists and record that choice. Do not combine a Trends index for one brand with estimated keyword volume for another.
Share of search vs share of voice, market share and brand lift
| Metric | What it measures | Planning role |
|---|---|---|
| Share of search | Relative branded search demand | Frequent signal of category interest and brand momentum |
| Share of voice | Relative advertising presence or spend | Competitive input to media weight and growth ambition |
| Market share | Relative sales, revenue or units | Commercial outcome the media strategy ultimately supports |
| Brand lift | Campaign-associated change in perception | Evidence that a defined campaign moved awareness or consideration |
| SEO share of visibility | Relative presence for non-brand search results | Search-channel diagnostic, not a measure of total brand demand |
A useful planning view places these signals on one timeline. Share of voice describes competitive input, brand lift reads a campaign effect, share of search tracks active interest and market share records commercial position. They may move at different speeds and should not be forced into a one-month causal story.
How to use share of search in a media plan
Set a competitive baseline
Record the level and trend before the campaign begins. A brand with 8% share of search facing a 45% leader has a different demand problem from a leader defending parity with its nearest competitor. The baseline helps define a realistic communication job and measurement period.
Read brand and non-brand demand together
Rising branded interest with flat category demand suggests the brand is taking relative attention. Rising branded interest alongside a category-wide surge may indicate the whole market is expanding. Pair the brand view with category terms, direct traffic and commercial outcomes before changing budget.
Use it as a slower allocation signal
Share of search is not a daily optimisation metric. Use a monthly series and a three-month rolling view for planning reviews, annotated with campaign launches, PR events, promotions and known market shocks. A sustained movement can support a strategic allocation discussion; a one-week spike should trigger diagnosis, not an automatic budget shift.
A reporting template planners can reuse
| Field | What to record |
|---|---|
| Market and category | The exact geographic and commercial scope |
| Competitor set | Brands in the denominator and the inclusion rationale |
| Query map | Terms, topics, spellings, sub-brands and exclusions per brand |
| Data source | Provider, database, search type and extraction date |
| Monthly brand values | Raw volume or common index for every included brand |
| Share calculation | Brand value divided by the category total |
| Rolling trend | Current month, three-month average and year-on-year change |
| Annotations | Campaigns, launches, PR, crises, promotions and methodology changes |
| Decision note | What the evidence changes - or why no action is warranted |
Common share of search mistakes
- Calling it search market share. The metric reflects relative search interest, not revenue or units sold.
- Changing competitors without restating history. A new denominator creates a false trend break unless earlier periods are recalculated.
- Mixing data sources. Provider estimates and Trends indices use different methods and cannot share one denominator.
- Ignoring ambiguous brand names. Unrelated searches can dominate a short or common brand term.
- Using Search Console for competitors. Search Console reports queries that surfaced your property, not total demand for other brands.
- Claiming media caused every rise. Product launches, distribution, news and earned attention also move brand searches.
- Optimising weekly. The metric is better suited to strategic trend reading than in-flight budget pacing.
Frequently asked questions
What is share of search?
Share of search is your brand's portion of branded search demand within a defined competitor set, market and period. It is calculated consistently for every included brand and tracked as a trend.
How do you calculate share of search?
Divide searches for your brand by the total searches for your brand plus every competitor in the defined set, then multiply by 100. Use the same data source, geography, time period and query rules for every brand.
Can Google Trends calculate share of search?
Yes, directionally. Compare the brands under identical settings, then divide each brand's Trends index by the combined index. Trends values are normalised rather than raw volumes, so preserve the comparison settings and treat the result as a relative trend.
Is share of search the same as Google Ads impression share?
No. Google Ads impression share is the percentage of eligible paid-search impressions your ads received. Share of search compares branded search demand across competing brands, whether or not an ad was served.
How often should share of search be reported?
Monthly reporting with a rolling three-month view is practical for most brands. Use longer comparisons where category search is small or highly seasonal, and annotate events that can create temporary spikes.