AI tools for finding and checking sources: web search with a link on every answer, academic paper search and extraction, and notebooks that answer from your own files.
Cheapest paid plan billed month to month, in USD, as listed on each profile.
Research AI tools help you find, read and cite sources, but they search different places. Perplexity answers from the open web with a link on every answer; Elicit and Consensus search academic papers, more than 138 million and 220 million respectively, and extract or synthesize study findings; Gemini Notebook answers only from documents you add. Each has a free plan, and individual paid tiers start between USD 4.99 and USD 20 a month.
21 tools
Clear filtersArena, formerly LMArena and Chatbot Arena, lets people compare AI model answers and vote; its terms call the service free, with no public price list.
Web AI tutor and activity builder for K-12 schools, with teacher monitoring of student sessions. Free for up to 80 users; paid licences from $3,000 a year.
For researchers and students who want to see how later papers cite a study; full text depends on the library license linked to the account.
SMMRY is an AI summarizer that condenses pasted text, web pages, documents and, on paid plans, YouTube videos and podcasts into short summaries.
iAsk is an AI search and answer engine that returns cited answers and summarizes web pages, text and uploaded documents.
Consensus is an AI academic search engine that answers research questions from peer-reviewed papers, with study filters, cited Deep reviews and an API.
Google's free research notebook for students and analysts who want every answer tied to a passage in documents they chose.
Elicit is an AI research assistant that searches more than 138 million papers and extracts study details into quoted tables for literature reviews.
Perplexity is an AI search service that answers questions from live web sources and links every answer to the pages behind it.
Start by deciding where your evidence lives. For current information on the open web, Perplexity builds each answer from live pages and links every one of them. General assistants such as Claude and ChatGPT also search the web with citations, so a search-first tool earns its place through features like daily Pro Searches, Research mode and scheduled Tasks. For published studies, Elicit and Consensus search academic papers instead of the web, and for a fixed set of documents you already hold, Gemini Notebook (formerly NotebookLM) answers only from the sources you add, with inline citations.
The paper tools differ in what they hand back. Elicit pulls study details such as design, population and outcomes into tables with a quote behind each value, and its Systematic Review workflow screens up to 5,000 papers on Pro. Consensus answers a question from the literature: a Deep review splits it into sub-questions, screens over 1,000 papers and typically analyzes up to 50. Consensus marks which citations were read in full text; the rest were read from the abstract only.
Each tool meters a different thing, which matters more than the headline price. Perplexity Free allows 3 Pro Searches a day and 1 Research query a month; Consensus Free allows 10 Pro messages and up to 3 Deep reviews a month; Gemini Notebook Standard caps each notebook at 50 sources; Elicit keeps paper search unlimited on every plan but gives no number for its shared monthly usage pool.
For web questions, read the Perplexity profile; for published studies, compare the Elicit and Consensus profiles; for your own documents, see Gemini Notebook. For a choice spanning research and writing, read Claude vs Perplexity alongside the Claude profile and the ChatGPT profile. The writing category covers turning checked material into a draft.
A source-focused notebook can also help discover material: distinguish sources already selected for an answer from discovery or Deep Research that brings in new material. Review newly added documents before treating the notebook as a closed evidence set. See the NotebookLM / Gemini Notebook profile for the available routes.
Free access, starting price and the date we last checked pricing, taken from each profile and listed A–Z. Not a ranking: prices keep the period, unit and currency the vendor shows.
| Tool | Free access | Paid plans from | Pricing checked | Consider it for |
|---|---|---|---|---|
| Arena | Free access available | Not confirmed | Comparing AI model answers by voting, without a paid plan | |
| ChatTube | Free trial only | $6.99 per month | Students and researchers who want to ask questions of a long YouTube lecture or tutorial and jump to the relevant timestamp instead of watching all of it | |
| Consensus | Free access available | USD 12/month | Finding and synthesizing published research | |
| Elicit | Free access available | USD 49 per user per month | Extracting study data from research papers | |
| Flint | Free access available | $3,000 per year | K-12 schools piloting an AI tutor that teachers can monitor | |
| Flowith | Free access available | $19.90 per month | Research, slides and web pages from one credit balance | |
| Gemini Notebook | Free access available | USD 4.99 per month | Cited answers from your own documents | |
| Genspark | Free access available | $24.99 per month | Turning a web research question into a sourced answer, fact check or finished document | |
| iAsk | Free access available | $9.95 per month | Quick cited answers and page summaries for study questions | |
| Perplexity | Free access available | USD 17 per month | Web research with linked sources | |
| Preuve AI | Free access available | $59 one-time | Checking whether a startup idea has demand and room before building it | |
| ResearchRabbit | Free access available | $12.50 per month | Widening a literature review from a few known papers through citations and co-authors | |
| Revisely | Free access available | $4.99 per month | Students and teachers who want to turn existing notes, PDFs or lecture videos into flashcards and quizzes, with a free tier for non-AI study sets | |
| SciSpace | Free access available | $12 a month billed annually; $20 billed monthly | Students and researchers reading a small set of papers who will check every cited passage | |
| Scite | Free access available | $20 per month billed yearly | Researchers and students checking how a paper has been cited | |
| Semantic Scholar | Free access available | Not confirmed | Searching and monitoring scientific literature for free, by hand or through an API | |
| SMMRY | Free access available | $9 per month | Quick summaries of articles, papers and videos | |
| SMRY | Free access available | $36 per year | Heavy readers who follow many sources and want summaries, article chat, audio and a searchable library, and who accept a daily cap on the free plan | |
| Studley | Free access available | $8.17 per month | Students who study from their own documents and recordings and want flashcards, quizzes, a tutor and podcasts from one upload, and who accept a small weekly allowance on the free plan | |
| Undermind | Free access available | $75 per month | Finding hard-to-locate papers on a specific research question | |
| Xapien | No free tier | Not confirmed | Compliance, legal and fundraising teams that vet many third parties |
Read the documented differences, then follow the links to each profile for its sources and plan details.
Task pages whose documented shortlist includes at least one tool from this category.
Our editorial judgement about what matters in this category, based on the plan structures we documented while building these profiles.
Claude and ChatGPT also search the web with citations, so web access alone is not the difference. Research tools differ in where they look and what they return: Elicit and Consensus search academic papers and extract or synthesize study results, Gemini Notebook stays inside the documents you add, and Perplexity adds search-first features such as daily Pro Searches, Research mode and scheduled Tasks.
All four have a free plan. Perplexity Free covers basic search with citations and 3 Pro Searches a day; Elicit Basic has unlimited paper search and summaries with report downloads; Consensus Free has unlimited paper search, 10 Pro messages and up to 3 Deep reviews a month; Gemini Notebook Standard allows 100 notebooks of up to 50 sources and 10 Deep Research runs a month.
Elicit fits when you must screen papers and extract data into columns: Pro screens up to 5,000 papers with 20 columns. Consensus fits when you want a synthesized answer across studies, with 15 Deep reviews a month on Pro and 200 on Deep. Gemini Notebook fits when you already hold the papers and need cited answers from them.
A citation points to the passage an answer used, but the summary can still misread it. Elicit warns that complex tables can be missed, Consensus reads some papers from the abstract only, and Google warns that Audio Overviews may contain inaccuracies. Open the cited passage before you carry a figure, date or condition into your own work.
Choose by whether you already hold the papers. Gemini Notebook (formerly NotebookLM) answers only from documents you add, with citations, up to 50 sources per notebook on Standard. Elicit and Consensus search academic papers for you, more than 138 million and 220 million respectively, and extract or synthesize findings. A common split is to find papers in Elicit, then question the ones you keep in a notebook.
Not the right category? Browse every tool in the directory, put two options side by side, or read how we check and correct these profiles.
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