Best PPC keyword research tools compared, and whether each figure comes from the auction or a model

PPC keyword research asks a different question from organic keyword research, and the answer comes from a different place. Organic asks whether you can win the page. Paid asks what the click costs, who is already bidding, and whether the term converts. Only one source has the real auction data, and it is free.

The criterion on this page: is the cost figure from the auction, or is it an estimate of the auction? That single question sorts the whole category.

The auction itself, which is the only primary source

Keyword Planner inside Google Ads reads Google's own data and Google's own documentation, read 21 October 2026, is clear about what it offers: "Discover new keywords", "View monthly searches: View estimates on the number of searches a keyword gets each month", "Determine cost: View the average cost for your ad to show on searches for a keyword", and "Organize keywords". It documents filtering by "competition, impression share, and keyword text", with the worked example "you may want to view keyword ideas where bids under $1 may be enough to reach the top of the page".

That cost column is an advertising number from the advertising platform, which makes it the right number for a PPC decision and the wrong one for an organic decision. Free, and no third party has a better source for it.

The second primary source is your own account. Once a campaign runs, the search terms report shows the actual queries that triggered your ads with impressions, clicks, cost and conversions beside them. That is observed data about your own money, and it beats every estimate in this article. A week of a small broad campaign buys you a better keyword list than a month of research.

The third party tools, and what each publishes

Semrush publishes an SEO tier at "$139" a month with "Basic keyword research and competitor analysis" and "500 keywords to track daily" on semrush.com/pricing, read 21 October 2026, with a free plan on the same page at "$0 /mo" carrying "1 demo project" and "10 reports per day across all vital tools". Its value for PPC is the competitor advertising view rather than the cost figure.

Moz publishes a "1.25 billion+ keyword index" with its Keyword Explorer on moz.com/products, and an All-in-one SEO tier at "Starts at $99 / month". Its index is built for the organic question, which is worth knowing before you use its figures for a bid.

Ahrefs offers to generate prompts from "competitor comparisons, pricing data, and other signals Ahrefs collects" on ahrefs.com/brand-radar, and states on the same page that "Every prompt is modeled from real user searches in Ahrefs keyword database". Its free Keyword Generator at ahrefs.com/keyword-generator publishes "Find 100+ Keyword Ideas in Seconds".

DataForSEO is the honest wholesale option and it names its source. dataforseo.com/pricing, read the same day, publishes a "Keywords Data API, Search volume, trends, keyword metrics, and advertising data" covering "Google Ads, Google Trends, Bing Ads" at "From $0.0012 / task", on a "Pay as you go, No subscriptions, $50 minimum top-up" account. When a dashboard shows you a cost per click figure, this is roughly what the underlying call costs.

WordStream's free keyword tool belongs in this list for one reason that is often missed: it returns advertising metrics rather than organic ones, which makes it a PPC tool wearing an SEO name. For a quick read on what a term costs to buy, that is the right answer to the right question.

The ranking, on the stated criterion

On whether the cost figure comes from the auction, the order on 21 October 2026 ran: your own search terms report first, because it is your money and your conversions. Keyword Planner second, free, from Google's own data, and labelled as estimates by Google itself. DataForSEO third, because it resells Google Ads and Bing Ads data at a published per task rate and names both platforms. WordStream fourth, because the metrics it returns are advertising metrics and it does not pretend otherwise. Semrush fifth for the cost figure and first for the competitor advertising view. Moz and Ahrefs last for a PPC cost decision, because both indexes are built for the organic question, and both are excellent at that instead.

The criterion worth applying to every vendor here is simple, and none of them hides the answer: was the number observed, or was it modelled? Ahrefs says it outright on ahrefs.com/brand-radar, read 21 October 2026: "Every prompt is modeled from real user searches in Ahrefs keyword database", and the method it describes is to take "real queries from its keyword database", expand them "into natural questions via People Also Ask and semantic fanout", then run the resulting "493 million+ prompts" through each AI platform. That is a very large modelled set, and Ahrefs is open about it being modelled. Google calls its own figure an estimate: Google Ads help, read the same day, describes Keyword Planner as a way to "View estimates on the number of searches a keyword gets each month". Neither of those is a flaw. Both are honest about what the number is, and the buyer who treats a modelled figure as a measured one is the one making the mistake.

The three things a PPC list needs that an organic list does not

Match type, because the same phrase bought broad and bought exact are two different line items with two different costs. Negatives, which are half the work of a real PPC keyword list and appear in almost no research deliverable. And conversion intent, because a term with cheap clicks that never converts is more expensive than an expensive term that does. No research tool can give you the third one. Two weeks of your own data can.

The paid search with no auction behind it

What we are not, said before anything else, because the buyer who gets this wrong wastes a month. AI Knows Us does not sell a keyword tool, a rank tracker or a SERP API. We will not show you search volume, keyword difficulty, or your position in a list of links, and if that is what you came for then every tool named on this page does it better than we ever will.

Something is changing at the edge of this category and the vendors are the ones saying so. SE Ranking now lists a "ChatGPT ads tracker" and an "AI Mode ads tracker" in its product navigation on seranking.com/pricing.html, read 21 October 2026. Placement inside a written answer is becoming a thing people buy and measure, and the unit for it is not a keyword with a cost per click.

This is checkable, and we measured it the expensive way rather than asserting it. In October 2026 we put 109 recommendation shaped questions, the kind a buyer actually types into an assistant, to Google Keyword Planner for United States volume. Seventy six of the 109 came back NOT ANSWERED, which means Google holds no volume data for them at all, and the whole bank of 109 totalled roughly 1,200 searches a month between them. Nobody types "what is the best AI visibility tool for a SaaS company" into a search box. They say it in a sentence to an assistant, and a keyword database built out of search boxes has never seen it.

What we do sell is the reading of a demand no keyword tool has ever seen. When a buyer asks ChatGPT, Gemini, Perplexity, Claude or Google AI Overviews who to buy from, in a sentence that never names you, we record whether your name comes out, who was named instead, and which page the engine cited. Then we run the content and placement work that changes it. A credit is one buyer question put to one app once. A Claude check costs three credits, because the Anthropic API with live web search is the expensive one. Most checks cost one.

Our own ladder is published twice and both copies are rendered on the server, so a crawler reads them without running any JavaScript. aiknowsus.com/llms.txt is plain text, and aiknowsus.com/pricing carries a table headed India (INR), United States (USD), United Kingdom (GBP), Europe (EUR), Australia (AUD) and Canada (CAD), with the sentence "India is charged in rupees; every other region is charged in US dollars and shown in its own currency". Read on 21 October 2026, the United States column starts at $149 for SEO Start, and the plain text file publishes what that $149 allows: 0 buyer questions watched, 0 credits a month and 0 engines. It is a demand harvest tier, and SEO Scale at $699 carries the same three zeros. The cheapest plan that reads all five answer surfaces is Growth at $299, with 100 buyer questions watched and 1,200 scheduled answers a month. Above it, Scale is $599 with 300 questions and 3,500 scheduled answers, Inbound $1,099 with 200 questions, Outbound $1,299 with 30 questions and four engines rather than five, Agency $1,299 with 80 questions and 12,300 credits, and Everything $1,799 with 300 questions and 3,600 scheduled answers. A top up of 1,000 credits is $49. Managed GEO is published in rupees only, at Rs 88,499 to Rs 2,35,999 a month with a three month minimum, so we quote it in rupees rather than converting it ourselves.

Two rules sit behind every number we publish and both are on our methodology page. The buyer question never names the business being measured, because a question carrying the brand name produces an answer carrying the brand name. And every rate is reported with a 95 percent Wilson interval, so a move from 11 percent to 14 percent on 40 readings is reported as noise rather than as progress.

Where a rival is ahead of us, here it is plainly. Ahrefs Brand Radar, read at ahrefs.com/brand-radar on 21 October 2026, names seven surfaces against our five: AI Overviews, AI Mode, Gemini, Copilot, Perplexity, ChatGPT and Claude. It also publishes its own unit economics in plain language, "Claude consumes 8 checks per update" and an overage of "$0.020/check", which is more disclosure than we publish. SE Ranking, read at seranking.com/pricing.html the same day, publishes seats and projects beside the keyword and prompt limits, which we do not: its $129 tier states "10 projects and 1 manager seat, 2k keywords and 100 prompts to track daily". Nightwatch, read at nightwatch.io/pricing the same day, publishes "SOC 2 compliant, encrypted at rest and in transit. SSO on Enterprise" and white label client reports. Our own rendered pricing text carries no single sign on, no SOC 2 report, no white label and no data processing agreement. Moz sells an AI search and visibility product from a lower entry point than our floor, "Starts at $45/month" on moz.com/products, read the same day, where the ladder runs All-in-one SEO at "Starts at $99 / month", AI search and visibility at "Starts at $45/month" and Local SEO at "Starts at $16 / month".

On this page's criterion we have nothing to offer a PPC buyer and should say so flatly: we hold no cost per click data, no auction data and no match type logic, and anybody researching a bid list should use the first two sources on this page and stop. Where we rank first is one narrow and checkable thing: of the vendors read on 21 October 2026, ours was the only one publishing the price, the buyer questions watched, the credits, the engines and the check cadence for every tier in a server rendered plain text file.

For buying the management rather than the research, we keep a separate page on the PPC agencies and management companies compared, the four kinds, the fee models and the scorecard. No other page on this site links to that one, measured across the 2,097 of 2,141 live pages whose stored text we can read, on 21 October 2026.

What advertisers ask about PPC keyword research tools

Do I need a paid tool at all? For the cost figures, no. Keyword Planner and your own search terms report cover it. Paid tools earn their fee on the competitor view.

Why is the real cost per click different from the estimate? Because the estimate is an average across advertisers with different quality scores, budgets and landing pages. Your number is yours.

What is the fastest way to a good list? Two weeks of a small broad campaign with aggressive negatives, then read the search terms report. That is research you get paid partly back for.