"LSI keywords" is one of SEO's most misunderstood terms. Technically, Latent Semantic Indexing is an old information-retrieval concept Google almost certainly does not use directly anymore. Practically, everyone means the same useful thing: the related terms and phrases that show Google your content covers a topic thoroughly — "electric range" and "battery life" on a page about electric cars, for instance.

Whatever you call them, topical coverage wins rankings in 2026. Here are five free ways to find these related terms.

Quick verdict

• Fastest dedicated tool: AutoRank LSI Extractor — paste text or a URL, get semantically related keywords instantly; 1 free run/day, no signup.
• Best $0 method stack: Google's own SERP features (below) — free forever, straight from the source.

1. AutoRank LSI Keyword Extractor — free, no signup

AutoRank's LSI Extractor does the job in one step: paste your draft or a competitor's URL and it returns semantically related keywords to weave into your content. It is one of three AutoRank tools ungated for anonymous users — 1 free run per day, no account needed. For a blogger optimizing a few articles a week, that is genuinely enough.

2. LSIGraph — the classic free tool

LSIGraph has been the go-to free LSI tool for years: enter a seed keyword, get a list of semantically related terms. The free tier covers casual use; heavy users hit limits. It is simple, fast, and purpose-built — a fine bookmark alongside a dedicated extractor.

3. Google's related searches + People Also Ask (free forever)

Scroll to the bottom of any Google result: "related searches" is Google literally telling you which terms it associates with your keyword. The "People Also Ask" boxes do the same for questions. Mine both for every target keyword — this data comes straight from Google's understanding of the topic, costs nothing, and never goes stale. (AutoRank's PAA Stealer automates the People Also Ask part, also with a free daily run.)

4. Wikipedia content mining (free)

Open the Wikipedia article on your topic and read it like a term list: the headings, bolded terms, "see also" section and linked articles are a human-curated map of everything semantically connected to your keyword. Fifteen minutes with Wikipedia routinely surfaces related terms no tool suggests — because tools count co-occurrence while Wikipedia encodes actual knowledge structure.

5. Competitor content reverse-engineering (free)

Take the top 3 ranking pages for your keyword and ask: which related terms do all three mention that your draft does not? Those shared terms are the topical baseline Google expects. You can do this by reading, or paste the URLs into an extractor and compare outputs. The gap between their coverage and yours is your optimization checklist.

How to actually use LSI keywords (without keyword stuffing)

The 2012 advice was "sprinkle these terms 15 times." The 2026 advice: use related terms naturally where they belong — in subheadings, in definitions, in examples. If a related term feels forced, skip it; Google rewards comprehensive coverage, not term density. One genuinely thorough article beats ten thin ones stuffed with synonyms.

FAQ

Are LSI keywords still a thing in 2026?

The acronym is outdated; the practice is not. Modern SEO calls it topical coverage or semantic SEO, and it matters more than ever as Google's AI understands topics rather than matching strings.

How many LSI keywords should I add per article?

There is no number. Cover the subtopics a reader would expect, use natural related terms as you write, then do one extraction pass to catch gaps. If you are counting, you are doing it wrong.

Can LSI keywords hurt my rankings?

Only if you stuff them unnaturally or drift off-topic. Related terms that genuinely belong in the article are always safe.

Sources

• Google Search Central documentation on helpful, people-first content and topic coverage
• AutoRank LSI Extractor: https://www.autorankenterprise.com/lsi-extractor