Share of Search: Definition, Calculation, and Marketing Impact
Discover what Share of Search means, how to calculate it, and why it’s vital for B2B brand tracking, demand forecasting, and competitive strategy.
What is “Share of Search”?
Share of Search (SoS) is the proportion of branded searches for your brand out of the total branded searches for all competing brands in your category, defined for a specific region and time period. In other words: it’s a behavioral proxy for how much of the category’s brand-seeking attention you command.
Compact formula: SoS = Branded searches for Brand A ÷ (Sum of branded searches for all brands in the category)
Why this matters: Pioneering work by Les Binet and the IPA/EffWorks program found that SoS often correlates with—and can lead—share of market, with the lead time varying by category purchase cycle, as summarized in the 2020 EffWorks presentation and coverage by WARC — Share of search can predict market share (2020) and the IPA’s EffWorks Global 2020 session page.
What Share of Search is not
Because “share of search” is used loosely, let’s draw clear boundaries.
Not SEO “share of voice.” SEO SoV estimates the share of organic visibility a domain earns across a defined keyword set (often non‑branded), based on rankings and click potential. It’s about search visibility, not brand demand. For methodology context, see SISTRIX’s sector visibility examples like Visibility leaders: gaming consoles.
Not Google Ads “impression share.” That paid metric is the percentage of impressions your ads received out of the total you were eligible for—driven by budget, bids, and ad rank. It reflects auction dynamics, not organic consumer demand, per Google Ads Help — About impression share.
Not the same as market share. SoS is a leading indicator and proxy for demand/mental availability. Treat it as the thermometer, not the fever.
Myths vs. facts
Myth: “SoS is just my SEO visibility.” Fact: SoS uses branded queries and consumer brand intent; SEO SoV is about rankings on a keyword set.
Myth: “If my impression share goes up, SoS will too.” Fact: Paid impression share can rise with budget alone; SoS tracks organic brand-seeking interest.
Myth: “SoS equals sales.” Fact: SoS often moves before sales; use it directionally and validate the lag in your category (weeks to months per EffWorks findings in 2020–2021 IPA updates).
Why SoS matters in 2025
It’s fast, behavior-based: Search is a near-real-time window into brand interest when sales/market data are delayed or siloed.
It supports planning: When SoS rises after brand campaigns, it indicates growing demand that can justify sustained or rebalanced investment.
It’s broadly observable: You can track your brand and competitors without panel data. The EffWorks work (Binet 2020; Hankins 2021) has made the practice reproducible across categories via IPA’s EffWorks resources.
Note on evolving search experiences: AI Overviews and zero‑click behaviors primarily hit informational, non‑branded queries. Multiple studies in 2024–2025 show diminished clicks when AI Overviews appear, especially on informational searches—see the Semrush AI Overviews study (2024–2025) and Ahrefs’ analysis of AI Overviews and clicks. Meanwhile, broader zero‑click trends persist; in 2024, SparkToro estimated only “about 37.4% of 1,000 US Google searches” generated clicks to the open web, highlighting long-term shifts in behavior (SparkToro 2024 zero‑click study). Because brand-tracking SoS relies on branded intent, current evidence suggests limited distortion compared to non‑branded measurements—but monitor your category.
How to calculate Share of Search (tool‑agnostic)
Define scope
Category: Be explicit (e.g., “US direct-to-consumer meal kits”).
Competitive set: 3–5 primary brands; revisit quarterly.
Regions and time: Choose the geographic market(s) and a window (e.g., last 12–24 months) at weekly or monthly cadence.
Build branded query lists per brand
Include: Official brand name, common misspellings, core sub-brands if they function as brands.
Exclude or qualify: Homonyms and generic words; add qualifiers (e.g., “Brandname software”) or negative terms to avoid unrelated meanings.
Collect data consistently
Google Trends (comparison mode) provides relative “interest over time” per term by region. Remember: values are normalized (0–100, where 100 is the peak in the selected scope). See Google Trends Help — normalization.
Search Console can validate your own branded query mix and seasonality (impressions/clicks), but it does not include competitor queries; use it for QA, not for the competitive numerator/denominator (Search Console Help — Performance report scope).
Third-party SEO tools (e.g., Ahrefs, Semrush) can help compile branded term lists and estimate volumes by region; keep the construct “branded-only” for SoS.
Normalize and compute
Within the same Trends comparison export, each series is scaled relative to the global peak across all compared terms. For each period, sum the normalized branded interest per brand, then compute SoS as:
SoS_brand_t = branded_interest_brand_t ÷ Σ(branded_interest_all_brands_t)
If you must combine multiple exports (because Trends limits comparisons), use an overlap anchor term to rescale—do so cautiously and document assumptions.
Smooth and annotate
Apply a 4‑week moving average (or 3‑month for monthly data) to reduce noise.
Annotate major events: brand campaigns, competitor launches, pricing changes, PR crises, distribution expansions.
Validate against outcomes
Correlate SoS with sales or market share and test lags typical for your category (weeks to months). EffWorks materials summarize category-dependent leads (e.g., longer for autos, shorter for utilities) via WARC’s 2020 coverage.
How to read SoS: from pattern to decision
Rising SoS → likely growing mental availability and demand. If pricing, availability, and conversion stay constant, sales often follow with a lag.
SoS up, sales flat → diagnose friction: distribution gaps, stock-outs, price shifts, website conversion, or channel mix.
SoS down, sales up → investigate short-term promotions or distribution changes that temporarily boost sales without building demand.
Competitive context matters → a +3pt gain is stronger if others are flat, weaker if the category is expanding for everyone.
Budget allocation → if SoS rises after broad-reach brand activity, you have evidence that investment is moving demand; if not, reassess creative, reach, or media mix.
Common pitfalls and how to fix them
Low volume (B2B/niche): Aggregate longer windows; use monthly cadence and 3‑month smoothing. Expand the branded list with legitimate variants. If volume is still too low, augment with directional indicators (site search, direct traffic) while noting limits.
Ambiguous brand names: Use qualifiers (e.g., “Acme CRM” vs. “acme”); maintain exclude terms. Consider focusing on sub-brands with unique names.
Mixing branded/non‑branded: Keep SoS clean—only branded queries in the numerator and denominator. Use SEO SoV separately for non‑branded performance.
Inconsistent regions/timeframes: Lock scope; don’t compare across countries without normalization.
Event shocks and sentiment spikes: Tag PR controversies or viral moments; don’t mistake curiosity spikes for purchase intent. Cross-check with sentiment and site engagement.
Over-reliance on a single tool: Triangulate—Trends for competitive direction, Search Console for your brand QA, and a third-party tool for list building. Document your method.
Quick-start toolkit (what good looks like)
Dashboard views
SoS trend by brand (stacked area to 100%).
YoY comparison view with campaign/event annotations.
SoS vs. sales/market share correlation with configurable lag.
Cadence and governance
Monthly reporting (most categories) or weekly for fast-moving ones.
Versioned branded term lists with inclusions/exclusions and rationale.
Quarterly review of the competitive set and region scope.
Decision hooks
“Trigger rules” to investigate ±3pt moves sustained for 4+ weeks.
Media readouts pairing reach/GRPs with SoS movement to assess efficiency.
FAQ
Does AI Overviews break SoS? Not generally. The largest click effects are on informational, non‑branded queries per the Semrush AI Overviews study (2024–2025). Still, monitor your category.
What if our brand name is generic? Build qualified query lists (add category modifiers), maintain excludes, and consider sub-brand tracking. Validate with your site’s branded query patterns in Search Console’s Performance report.
Can I compute SoS from Search Console alone? No; Search Console doesn’t provide competitor queries. Use it for your brand QA and rely on cross-brand sources like Google Trends, which explains its normalization in Trends Help.
How strong is the link to market share? Multiple EffWorks sessions (Binet 2020; Hankins 2021) and trade coverage report meaningful correlations and category-dependent lead times—see IPA’s EffWorks Global 2020 and 2021 update, plus Marketing Week’s SoS coverage hub (2024–2025). Treat SoS as directional; validate in your own data.
Bottom line
Share of Search is a simple, powerful way to track category-level brand demand. Use it alongside sales, distribution, and media data: define your competitive set, build clean branded query lists, compute SoS consistently, and read it with context. Get the basics right, and SoS becomes a practical early-warning and planning signal for brand investment.
