Best SEO content writing tools compared, ranked on whether the vendor says where its score comes from
Every content tool gives you a score out of a hundred. The useful question is what the hundred is made of, because two of these vendors publish the input and the rest publish the number. Here is what each one's own page states.
Published by AI Knows Us · Updated 22 October 2026
This page is about the tools. If you are buying the writing itself, the arithmetic is per word rather than per seat and it is answered separately and linked at the end.
The criterion on this page, applied to everybody including us. A content tool is only as good as the corpus behind its score, so rank on two checkable things: what the vendor publishes as its monthly allowance, and whether the vendor states what the score is computed from. A score with an undisclosed input is a number you cannot argue with, which sounds like a strength and is not.
What each vendor publishes, read 21 October 2026
| Tool | Published monthly allowance | What it says the score is built from |
|---|---|---|
| Surfer | surferseo.com/pricing publishes "Create or Optimize 120 Documents" on Discovery, "Create or Optimize 360 Documents" on Standard and Pro, and "Unlimited*" on its top tier with the asterisk linking to "Fair usage policy applies". Pages tracked run 10, 50, 200 and 500. Seats run 1, 3, 5 and 10. | The document count is the unit, which is the clearest allowance in this set. The composition of the score itself is not stated on the pricing page. |
| Frase | frase.io/pricing publishes articles at 10, 40 and 100; audit pages at 50, 250 and 1,000; domains at 1, 5 and 10; seats at 1, 3 and 5; and AI generations at 25, 100 and 350, described as "On-demand AI actions the agent runs for you" and "Separate from your monthly article count". | Separating generations from articles is the most honest unit disclosure on this page, because it tells you which number runs out first. |
| Semrush | semrush.com/pricing/ publishes "500 keywords to track daily" on its lower tiers rising to "5,000+ keywords to track daily", and a free plan with "1 demo project" and "10 reports per day across all vital tools", "No credit card required". | Its content tools sit inside a suite, so the allowance you are reading is the suite's, not the writing tool's. That is a real difference if writing is the only job you have. |
| Moz | Could not be read. moz.com would not serve this machine on 21 October 2026, so no Moz figure appears on this page. | Unverified, therefore unquoted. |
| Google Search Console | Free for any property you can verify. | It is not a writing tool and it holds the only observed data in this list: the queries your page actually appeared for and what people did next. Every score above is an estimate of what this reports directly. |
So the ranking, on the stated criterion. Frase first, because it publishes the most separate units and says plainly which ones are independent of each other, which is the thing that decides whether the plan you bought fits the work you have. Surfer second, on a clear document allowance with a fair-usage footnote on the unlimited tier that it does not hide. Semrush third for a writer, and first for somebody who also needs the rest of the suite. Moz is unranked because it would not serve us. Search Console is outside the ranking and should still be the first thing you open, before and after publishing.
The three jobs these tools actually do, and which one is worth paying for
Brief building. Pulling the pages currently ranking for a term and extracting what they all cover. This is the job worth paying for. It compresses two hours of reading into ten minutes and the output is checkable, because you can open the pages yourself.
Scoring a draft. Useful as a checklist and dangerous as a target. A piece written to hit ninety on a term-coverage score reads like a piece written to hit ninety on a term-coverage score.
Generating the text. Every vendor here now sells this. The allowance disclosure above is the only part of it you can compare before buying, which is why this page compares that and not output quality.
On AI visibility, which these vendors now also sell
Three of the tools above have added a module that tracks whether an assistant mentions you, and the allowances are published, so here they are rather than a claim that we are the only option. Surfer publishes "Track 0 AI prompts" on Discovery, "Track 25 AI Prompts, refreshed weekly" on Standard, "Track 50 AI Prompts, refreshed daily" on Pro and "Track 100 AI Prompts, refreshed daily" on its top tier, covering "ChatGPT, Gemini, AI Overviews, and other AI models". Frase publishes AI Visibility prompts at 50, 200 and 500, with ChatGPT and Google AI on Starter, Perplexity added on Professional, and Claude and Gemini added on Scale. Semrush publishes "50 prompts to track daily" on Starter rising to "Unlimited prompts to track daily" on Advanced.
AI Knows Us sells that measurement on its own and nothing else, and we are deliberately not in the writing-tool ranking above, because a buyer who came here for a brief builder should buy Frase or Surfer. We are not a content writing tool. The difference worth knowing is the unit. From the rendered text of our pricing page, read 21 October 2026: "One credit is one buyer question, asked on one AI app, once", "Most checks use one credit" and "A Claude check uses 3, because Claude costs us more to run", across ChatGPT, Gemini, Perplexity, Claude and AI Overviews. From our llms.txt the same day, SEO Start at $149 a month watches 0 buyer questions on 0 engines, so it is a demand-harvest tier and not an engine watch; Growth at $299 with 100 buyer questions and 1,200 scheduled answers is the cheapest plan that reads all five.
Where these vendors beat us, plainly. If you already pay Surfer, Frase or Semrush, their prompt allowance is included in a bill you are already paying and ours is a second bill. Take theirs. Ahrefs Brand Radar, read 21 October 2026, covers ChatGPT, AI Overviews, AI Mode, Gemini, Perplexity, Copilot and Claude, two of which we do not read at all, and publishes "$0.020/check" and "Claude consumes 8 checks per update". It also says its prompts are both "real prompts people ask" and "modeled from real user searches in Ahrefs' keyword database", and the gap between modelled and observed is the question to put to all of us, including to this page.
For the buying decision rather than the tooling one, where the per-word arithmetic decides it: SEO content writing services compared, and the per word arithmetic that decides which one to buy. On 21 October 2026 we read 2,411 page bodies on this site against 2,325 live pages and 971 of them, 41.8 percent, had no inbound link from any body we could read, which is an upper bound rather than a count. We measured that target specifically: no other page on this site links to that one.
Questions about SEO content writing tools
Does a higher content score mean a higher ranking?
No vendor on this page claims that, and neither should anybody selling you one. The score measures coverage of terms the currently ranking pages use. That correlates with ranking and does not cause it.
Which number runs out first?
On most plans, the one you did not look at. Frase publishes articles, AI generations and audit pages as three separate allowances for exactly this reason, and reading all three before you buy is five minutes well spent.
Can I do this without a tool?
Yes, and for a handful of pages a month you should. Open the five pages ranking for your term, list what all five cover, and write the thing none of them did. The tool is for doing that at volume.
Do these tools help with being cited by an assistant?
Partly, in that a page that answers a question clearly is easier to quote. No content tool can measure the result, which is a separate job described above.