The short answer
Choose by the question, not account size
Keyword Planner fits a focused Google Ads job: discover terms, examine estimated demand and build a campaign forecast. A large advertiser can use it too. Semrush is worth considering when someone regularly needs organic competitor comparisons, keyword gaps, position tracking or site research.
You may use both. Do not buy a subscription just to collect a larger keyword list. First name the decision that the additional research will change.
What changes in real work?
| Question | Keyword Planner | Semrush |
|---|---|---|
| What could a Search campaign target? | Keyword ideas and Google Ads forecasts with the plan’s assumptions. | Keyword and competitor research can add context; it is not your Google Ads account forecast. |
| Which organic topics are competitors visible for? | A website can seed keyword ideas. That is not a full organic ranking-gap report. | Keyword Gap compares domains or pages, with organic or paid data selected. |
| How hard is an organic ranking? | The competition metric describes advertisers, not organic SEO difficulty. | Keyword difficulty is a modeled SEO metric. Inspect the actual results and your ability to answer the query. |
| What will my business earn? | Estimates are planning inputs. Actual results depend on the campaign and market. | Competitor estimates and rankings are not your conversions, margins or sales. |
| What does access cost? | No separate tool subscription; Google Ads account setup and billing information are required for basic access. Ad spend is separate. | Limited free access and paid plans. Price the exact toolkit, limits, users and billing term you need. |
Use your own Google Ads account evidence to assess an active campaign. Planning tools cannot replace the actual search terms, accepted inquiries and sales records.
Compare the selected plan, not the brand
At the October 18, 2026 check, Semrush’s published USD SEO plan was $139 monthly or $117.33 per month billed annually. Its Starter SEO + AI Search bundle was $199 monthly or $165.17 per month billed annually.
Those are distinct offers. Do not assume every advertised AI, traffic, local, content or advertising feature comes with the entry SEO plan. Check the exact feature and usage limit in the selected plan; additional users and products can add cost. Confirm the invoice, taxes, promotion, renewal and cancellation terms before purchase.
Check Semrush’s current plans and prices. A monthly equivalent billed annually is not a month-to-month commitment.
Who should choose each?
Start with Keyword Planner
You need a defined Google Search campaign plan, its location and budget assumptions, and a shortlist of relevant terms. A broader subscription may add no useful decision.
Consider Semrush
You have a recurring research owner and questions about competitor coverage, organic opportunities or rankings. Trial the required workflow and confirm the subscription includes it.
Use both for connected work
An SEO opportunity can prompt a paid-search test, but evaluate each channel on its own terms. Keep the research source and assumptions attached to every number.
Worked example · Illustrative research brief
The same service, two different questions
A fictional commercial cleaning company wants more office-cleaning inquiries in Portland, Oregon. It serves offices; it does not provide residential cleaning or recruit through this campaign. This example shows the research decisions. It is not a live tool test, export, volume estimate or client result.
- Brief shared by both tools
- Office cleaning; Portland service area; English; the same seed terms and review date. Record each tool’s available geography and database. If one report is national and another local, label the mismatch instead of comparing their volumes directly.
- Keyword Planner question
- Which relevant terms belong in a possible Search campaign? Start with “office cleaning Portland” and “commercial cleaning services.” Review actual ideas, targeting, match assumptions and the forecast before proposing a budget.
- Semrush question
- What relevant organic topics or pages are established competitors visible for? Compare the business and relevant domains in Keyword Gap, select organic data, then inspect the search results and landing pages before treating a missing term as an opportunity.
- Terms to separate
- Office-cleaning terms may fit the offer. Residential-cleaning and cleaning-job searches do not fit this brief. A checklist query may deserve useful educational content without belonging in the first paid campaign. Review negative keyword match behavior before applying exclusions.
- Evidence still required
- Actual exports, selected settings, current results and the company’s service capacity. Leave missing values blank. A tool’s keyword gap does not establish that a page is worth creating.
- Decision after the test
- If only the ad plan changes, use Keyword Planner and keep the brief. If competitor research identifies useful recurring work with an owner, compare the least sufficient Semrush plan with the time needed to use it. No changed decision means no demonstrated reason to subscribe.
Keep unlike metrics separate
Record the settings
Save country or location, language, date range, network, database and device where available. Document settings a tool cannot match. Keep brand and non-brand terms distinct.
Name what the number measures
Google’s historical search statistics and campaign forecasts answer different questions. Historical metrics can include close variants; forecasts also depend on the plan. An ad-competition label is not an organic ranking score.
Inspect the buying question
Open relevant search results and ask whether the business can answer that specific need. A high-volume keyword can still attract the wrong visitor. An estimated low-volume term may be useful if it expresses a real service need.
Keep the conclusion modest
Do not average conflicting estimates into a supposedly precise answer. Record the mismatch and the decision you can still make. Validate a published page or live campaign with its own search, inquiry and sales evidence.
Use one research brief for both tools
The worksheet keeps the buyer, geography, keyword group, source, settings, unknowns and proposed action together. Use it to decide whether the additional research changes paid work, a useful website page or neither.
Download the blank worksheet · CSVNo email required. This is a research worksheet, not a campaign-upload file. Keep private account exports in your own storage.
Official sources and limits
- Google: use Keyword Planner: access, ideas and planning workflow.
- Google: Keyword Planner forecasts: historical metrics, competition and forecast definitions.
- Semrush: Keyword Gap: competitor comparison workflow.
- Semrush: keyword difficulty: the SEO metric and its limitations.
- Semrush: plans and pricing: checked October 18, 2026; verify again before buying.
The brief and buying recommendations are our editorial judgment. No subscription, ranking or revenue outcome is guaranteed.
Turn the research into useful marketing work
Stan Consulting can scope paid-search planning, campaign management and the website content that supports your offers. Bring the service, market and decision you need to make. We agree scope and price before implementation.
For broader software choices, see Google Ads tools and SEO and AI-search tools. For a page already receiving visibility, use the safe content update guide.