Semrush vs Google Keyword Planner: Not the Same Job

Semrush and Google Keyword Planner are not really competitors: they were built for different jobs. Google Keyword Planner is a free tool inside Google Ads, designed to help advertisers plan campaigns, so its core metrics are bid estimates and grouped search volumes. Semrush is a paid SEO platform (from $139, about £102, per month as of July 2026, USD, ex VAT) that adds keyword difficulty, search intent, SERP data and competitor research. Our short answer: use Semrush for SEO keyword research and treat Keyword Planner as a free cross-check on demand and commercial value. This post explains the structural differences and who can genuinely stay free-only.

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This comparison is part of our SEO tools hub, where we cover everything we use in client work.

Semrush vs Google Keyword Planner: what is the real difference?

The fundamental difference between Semrush and Google Keyword Planner is purpose. Keyword Planner exists to sell Google Ads. You need a Google Ads account to open it, and Google’s own documentation frames every metric around advertising: the “competition” column counts how many advertisers bid on a keyword (nothing to do with organic difficulty), and the top of page bid columns show roughly the 20th and 80th percentile of what advertisers have historically paid. Semrush was built for organic search: it scores keyword difficulty against the pages actually ranking, labels search intent, shows which SERP features appear, and lets you see the exact keywords a competitor ranks for. One tool answers “what would this cost to advertise on?”; the other answers “can we rank for this, and is it worth it?”. Judging either tool by the other’s job is where most confusion in the Semrush vs Google Keyword Planner debate comes from.

Why does Keyword Planner show volume ranges instead of exact numbers?

Google Keyword Planner shows broad volume buckets (10 to 100, 100 to 1K, 1K to 10K, 10K to 100K) to accounts that are not spending enough on ads. As of July 2026, only accounts with sufficient active campaign spend see more precise average monthly searches; everyone else gets the ranges. Those buckets are wide: a phrase searched around 1,200 times a month and one searched 9,500 times sit in the same “1K to 10K” row, so you cannot tell which is the bigger opportunity. Two further quirks matter for SEO. Google’s stats combine a keyword with its close variants (plurals, close spellings), so long-tail phrasings get merged into one line. And the figures are rounded, so volumes across locations often fail to add up. Semrush shows one modelled estimate per distinct phrase instead. Semrush numbers are estimates too, but they are estimates you can actually compare.

What does each tool show for the same keyword?

Run the same keyword through both tools and the reports barely overlap. The table below is illustrative: it describes what each column structurally contains, not specific figures.

What you see	Google Keyword Planner	Semrush (Keyword Overview)
Monthly volume	Broad bucket (e.g. 1K to 10K) unless your account has active ad spend	A single modelled estimate per phrase, per country
Difficulty	None. “Competition” measures advertiser density, not organic difficulty	Keyword difficulty % scored against the current ranking pages
Search intent	Not shown	Labelled (informational, commercial, transactional, navigational)
Cost data	Top of page bid, low and high range (roughly 20th and 80th percentile of historical bids)	CPC estimate and competitive density
Keyword variants	Close variants merged into one row	Each phrasing reported separately, with variation and question lists
SERP context	None	SERP features present, plus the pages currently ranking
Trend	12 month search trend	12 month search trend, plus global volume split

Is Google Keyword Planner good for SEO?

Google Keyword Planner is partially good for SEO: it is a useful input, not a research platform. The data comes straight from Google, it costs nothing, and the bid columns are an honest signal of commercial value (advertisers do not keep paying for terms that never convert). Where it falls down for organic work:

Pros for SEO

• Free, and the demand data is Google’s own
• Bid ranges reveal which keywords make money
• Decent seed-idea generator from a URL or a product

Cons for SEO

• Volume ranges are too coarse to prioritise with
• No organic difficulty score and no SERP data
• Close variant grouping hides the long tail
• Requires a Google Ads account, and the interface pushes you towards creating campaigns

If you want a keyword planner alternative built for organic research, that is exactly the gap Semrush and its rivals fill: our comparison of the best Semrush alternatives covers the options at every budget.

How do we use both tools together?

Our agency workflow uses Semrush for the research and Keyword Planner as the free second opinion. If you have never opened it, how to use Google Keyword Planner is simple: in Google Ads open the Tools menu, choose Keyword Planner, and start with “Discover new keywords”. The combined workflow looks like this:

1. Build the keyword list in Semrush’s Keyword Magic Tool, filtered by intent and difficulty (our full process is in our Semrush keyword research walkthrough).
2. Paste the shortlist into Keyword Planner’s “Get search volume and forecasts” to sanity-check that Google sees real demand.
3. Use the top of page bid columns to rank keywords by commercial value: high bids mean advertisers are making money on that term.
4. Note which phrasings Keyword Planner merges as close variants; that tells you which variations one page can cover.
5. Map keywords to pages, then track them: our guide on how to track keyword rankings covers the setup.

The same research-first approach sits behind client results like TWF’s 44% revenue growth and Circa London’s 40% rise in enquiries.

Who can stay free-only?

Some sites never need a paid keyword tool. Keyword Planner is free with a Google Ads account, and the free Semrush account softens the gap further: as of July 2026 it includes 10 analytics queries a day, one project, 10 tracked keywords and a 100 page site audit. Keyword Planner is only one of eight genuinely free options; we tested them all on a single niche in our guide to free keyword research tools. If your site already earns impressions, Search Console keyword research is the free source neither tool can match, because the data is your own. Free-only is a reasonable long-term setup if you can tick most of these:

• You already run Google Ads, so Keyword Planner shows you precise volumes anyway
• You target a handful of local keywords, not hundreds
• You have no need for competitor keyword research
• Content is occasional, not a weekly publishing operation
• Nobody is paying you to deliver rankings

Agencies, ecommerce sites and anyone in a competitive niche will outgrow that within weeks. If the $139 (about £102) per month Semrush entry price is the blocker, a mid-priced platform is the sensible middle ground: see our SE Ranking review and our SE Ranking vs Semrush comparison before defaulting to the biggest name.

Not sure which setup your site actually needs? We will tell you honestly, even if the answer is “stay free for now”.

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Semrush vs Google Keyword Planner: FAQs

Is Google Keyword Planner free?

Yes. Google Keyword Planner is free, but it lives inside Google Ads, so you need a Google Ads account to use it, and Google prompts you to complete account setup along the way. You do not have to run ads to research keywords, though accounts without active spend see volume ranges rather than precise figures.

Does Google Keyword Planner show exact search volumes?

Not for most people. As of July 2026, accounts without sufficient active ad spend see bucketed ranges such as 1K to 10K. Accounts running campaigns with enough spend see more precise average monthly searches. Even then, figures are rounded and close variants are combined, so “exact” overstates it.

Is Semrush data more accurate than Google’s?

Neither is exact. Google’s data is first-party but heavily rounded, bucketed into ranges, and merged across close variants. Semrush volumes are modelled estimates, but each distinct phrase gets its own figure, which makes keywords comparable against each other. For prioritising organic work, comparable beats first-party-but-blurred.

Can I use Google Keyword Planner without running ads?

Yes. You can create a Google Ads account, skip or pause campaign creation, and use Keyword Planner for research. Without active spend you only see volume ranges, and the interface keeps nudging you towards launching a campaign.

What is the best keyword planner alternative for SEO?

Semrush is the strongest all-round keyword planner alternative for organic research, with difficulty scores, intent labels and competitor keyword data that Keyword Planner lacks. Plans start at $139 (about £102) per month ($117.33, about £86, per month billed annually) as of July 2026, USD, ex VAT. Platforms such as SE Ranking cover the same core jobs at a lower price; our Semrush alternatives guide compares them.

Which should a small business start with?

Start with Google Keyword Planner plus a free Semrush account: that costs nothing and covers basic demand checks, 10 analytics queries a day and 10 tracked keywords (as of July 2026). Move to a paid plan when keyword research becomes a regular task rather than an occasional one.

Why do Semrush and Keyword Planner show different volumes for the same keyword?

Because they measure differently. Google reports its own (rounded, range-bucketed) search data and folds close variants into one figure. Semrush models volume per distinct phrase from its own datasets. A merged Google figure often looks bigger than any single Semrush phrase, and both are twelve month averages, not live counts.