AI Summarization Tool Comparison 2026: Google NotebookLM, ChatPDF, Adobe Acrobat AI and 7 More (Pricing & Free Plans)

When choosing an AI summarization tool, many people hesitate over pricing structures, the availability of a free plan, and the level of Japanese support. It is also important to compare features that fit your use cases, such as whether the tool works in a browser only or if it covers meeting transcription.

This article provides a complete comparison of 10 major tools, including Google NotebookLM and ChatPDF, based on AIpedia data as of November 2026. We outline each tool's pricing, free plan availability, Japanese support status, and platforms, along with specific strengths and things to note.

We also explain recommendations by goal, such as document analysis and creating meeting minutes, and how to choose without making mistakes. Review the key information you need before adoption and find the best AI summarization tool for you.

What Are AI Summarization Tools? What They Can Do and What to Know Before Choosing

AI summarization tools help extract key information from long PDFs, meeting audio, or web articles in a short amount of time. For example, Google NotebookLM can answer questions based on uploaded documents, while ChatPDF allows you to review PDF content through conversation. This category also includes tools like Otter.ai and Fathom that transcribe meetings in real time and automatically organize key points and action items.

• Summarize the full text of PDFs or documents into shorter versions and display source pages to verify content
• Automatically record meetings on Zoom or Google Meet and separate and record speech by speaker
• Generate AI summaries immediately after a meeting ends, extracting decisions and action items
• Convert key points from academic papers into flashcards or automatically highlight important sections
• Extract key points from web pages or YouTube videos and save and share them as notes

When choosing a tool, pay attention to the differences in free plan limits. For example, Fathom offers unlimited recording and summarization on its free plan, while tl;dv restricts AI summarization features even for free users. Japanese support accuracy also varies by tool; Otter.ai and QuillBot Summarizer are reported to have lower accuracy compared to English.

Additionally, check the available platforms. Adobe Acrobat AI is available on the web, as well as desktop apps for Windows and Mac, and on smartphones. In contrast, Glasp is a tool used via Chrome or Safari extensions and its web version, with no mobile app. Options range from lightweight tools for individuals to security-focused services for businesses, so it is important to choose one that fits your specific use case.

Comparison Table of Top 10 Tools (Pricing, Japanese Support, Platforms)

Tool	AIpedia rating	Main plans	Japanese support	Platforms
Google NotebookLM	4.5	Free (basic features) / Google AI Pro (formerly Google AI Premium) $19.99/month / Google AI Ultra $249.99/month	Supported (Japanese UI, Japanese source support)	Web
ChatPDF	4.2	Free plan (2 files per day, up to 120 pages) / Plus $15/month (50 files/day, 2000 pages, unlimited questions) / Enterprise (contact sales)	Supported	Web
Adobe Acrobat AI	4.4	Acrobat Standard $12.99/month / Acrobat Pro $19.99/month / AI Assistant add-on $4.99/month	Supported	Web, Windows, Mac, iOS, and others
Otter.ai	4.1	Basic Free (600 minutes per month) / Pro $16.99/month (6,000 minutes per month) / Business $30/user/month	Partially supported	Web, iOS, Android, Chrome extension
Fathom	4.4	Free: Unlimited recording, transcription, and AI summaries / Premium: $19/user/month (CRM integration, advanced features) / Team Edition: $29/user/month	Partially supported	Web, macOS, Windows
tl;dv	4.3	Free (unlimited recording and transcription) / Pro $29/month / Business $98/month	Supported (Japanese transcription and summary support)	Web, Chrome extension
Fireflies.ai	4.3	Free $0 (20 AI summaries per month) / Pro $10/user/month (annual billing) / Business $19/user/month (annual billing)	Supported	Web, iOS, Android, Chrome extension
Glasp	4.2	Free (basic features) / Pro $12/month	Supported (Japanese UI, Japanese content support)	Chrome extension, Safari extension, Web
QuillBot Summarizer	4.1	Free (summarize up to 2,500 words) / Premium $9.95/month ($49.95/year with annual billing, summarize up to 6,000 words)	Partially supported	Web, Chrome extension, Word integration, Google Docs integration
Scholarcy	4	Browser extension Free / Scholarcy Library $4.99/month ($45/year with annual billing) / For educational institutions $8,000+/year	Not supported	Web, Chrome extension, Edge extension, Firefox extension

Ratings are based on a 5-point scale by the AIpedia editorial team. Pricing and plans may change. Please check the official website of each tool for the latest information before signing up.

Features, Pricing, and Best Use Cases for 10 Tools

1. Google NotebookLM

Google NotebookLM is an AI research assistant that generates answers and summaries using only uploaded documents as information sources. It enables accurate analysis based on specific documents, reducing the risk of hallucinations (AI-generated falsehoods). It also features a function that explains document content in podcast-style audio.

• Strengths: Supports diverse sources such as PDFs and web pages. Its large 1-million-token context window allows for batch processing of massive amounts of materials. Accurate citation display makes it easy to verify answers.
• Strengths: The Audio Overview feature automatically generates audio where two AI hosts interact to explain the content. This allows you to understand document content without using your eyes, such as during a commute.
• Strengths: Basic features are available for free and can be started immediately with a Google account. Organizing and managing materials by project in a notebook format helps improve research efficiency.
• Things to note: It cannot provide answers based on general knowledge outside of uploaded sources (except for the Deep Research feature). It is not suitable for general questions but is designed for deep analysis of specific documents.
• Things to note: The audio quality of Japanese Audio Overviews is reportedly slightly inferior to English. Additionally, the free plan has a limit of 50 AI queries per day, so caution is needed for extensive research.

Pricing: Free (basic features) / Google AI Pro (formerly Google AI Premium) $19.99/month / Google AI Ultra $249.99/month

Best for: Individuals who need to read and understand large volumes of documents, such as academic papers or market research reports. Also recommended for those who want to review document content via audio while traveling, or business professionals seeking reliable, source-based answers.

View detailed features, pricing, and FAQ for Google NotebookLM

2. ChatPDF

ChatPDF is a web service that allows you to upload PDF files and interact with AI to ask questions and get summaries. It streamlines understanding long-form content like papers or contracts. Its design makes it easy to verify answer accuracy against the original text by displaying citation page numbers.

• Strengths: No account registration required; start AI conversations immediately by dragging and dropping files.
• Strengths: Supports simultaneous upload of multiple PDFs and cross-document questioning, enabling comparative analysis.
• Strengths: Allows questions and answers in Japanese. You can request a Japanese summary of an English PDF ("Summarize this in Japanese") to reduce the burden of reading English papers or materials.
• Things to note: Accuracy may be lower for scanned image-based PDFs or information within graphs and tables.
• Things to note: The free plan is limited to 2 files per day and 120 pages per file. It does not support formats other than PDF (such as Word or PowerPoint).
• Things to note: AI answers may occasionally misinterpret PDF content, so verify important information against the original text on the cited page.

Pricing: Free plan (2 files/day, up to 120 pages) / Plus $15/month (50 files/day, 2000 pages, unlimited questions) / Enterprise (contact sales)

Best for: Individuals who want to easily use PDF-specific interactive Q&A for tasks like reading academic papers or analyzing contracts.

3. Adobe Acrobat AI

Adobe Acrobat AI is an AI assistant feature integrated into Adobe Acrobat, the world standard for PDF software. It leverages generative AI to help summarize lengthy PDF documents and support question-and-answer interactions in a chat format. Even for documents ranging from dozens to hundreds of pages, such as contracts or academic papers, it can extract key points and provide concise summaries.

• Strengths: It integrates seamlessly into existing Acrobat workflows, providing a reliable environment specialized for PDF processing.
• Strengths: It features the ability to search and compare information across multiple PDFs, improving the efficiency of processing large volumes of documents.
• Strengths: It implements enterprise-grade security, supporting use in legal and financial sectors.
• Things to note: To use AI features, you must add the AI Assistant add-on ($4.99/month) on top of an Acrobat Standard or Pro plan.
• Things to note: Support for file formats other than PDF is limited, and it cannot be used in offline environments.

Pricing: Acrobat Standard $12.99/month / Acrobat Pro $19.99/month / AI Assistant add-on $4.99/month

Best for: Business professionals, legal staff, and researchers who handle large volumes of PDF documents. It is suitable for those who want to efficiently understand and utilize long-form documents while leveraging their existing Adobe product environment.

4. Otter.ai

Otter.ai is an AI-powered tool for meeting transcription and summarization. It automatically joins online meetings on platforms like Zoom or Google Meet and transcribes speech into text in real time. Additionally, it automatically extracts and provides key points and action items using AI.

• Strengths: Speaker identification technology accurately separates and records each participant's remarks. Also, with the Otter AI Chat feature, you can ask questions about past meeting data using natural language.
• Strengths: It integrates with external tools like Slack, Notion, and Salesforce, streamlining post-meeting follow-up tasks. It also includes a customer reaction detection feature for sales teams.
• Strengths: The free Basic plan allows up to 600 minutes of transcription per month, and the mobile app (iOS/Android) can record in-person meetings or interviews.
• Things to note: While English transcription accuracy is high, Japanese may have noticeable misrecognitions of proper nouns and technical terms. Also, since audio data is stored in the cloud, you must verify internal policies for confidential meetings.

Pricing: Basic Free (600 minutes/month) / Pro $16.99/month (6,000 minutes/month) / Business $30/user/month / Enterprise (contact sales)

Best for: Business professionals with many online meetings in English-speaking regions, and managers who want to streamline meeting minutes management for their teams. It is also suitable for sales teams looking to analyze sales calls or leverage CRM integration. However, if Japanese accuracy is your top priority, consider using it alongside other tools.

View detailed features, pricing, and FAQ for Otter.ai

5. Fathom

Fathom is a tool that uses AI to automatically create meeting summaries and notes. It records and transcribes video conferences on Zoom, Microsoft Teams, and Google Meet in real time. Within seconds of the meeting ending, it generates a structured summary.

• Strengths: Unlimited recording, transcription, and AI summarization are available on the free plan. A key feature is that summaries are completed within seconds of a meeting ending.
• Strengths: Integrations with CRMs like Salesforce and HubSpot are possible. It also offers robust integrations with Slack, Notion, and Google Docs.
• Things to note: Japanese transcription and summarization accuracy may be lower than for English. It does not support in-person meetings.

Pricing: Free: Unlimited recording, transcription, and AI summarization / Premium: $19/user/month (CRM integrations, advanced features) / Team Edition: $29/user/month

Best for: Individuals and teams who want to automate online meeting records while keeping costs low. It is also suitable for those who want to use automatic CRM logging in sales activities.

6. tl;dv

tl;dv is a tool that automatically records and transcribes online meetings on Zoom or Google Meet, with AI generating summaries. It automatically extracts key points and action items to create structured notes.

• Strengths: Unlimited recording and transcription are available on the free plan.
• Strengths: Supports major platforms including Zoom, Google Meet, and Microsoft Teams.
• Strengths: Integrates with CRM tools like Salesforce and HubSpot to streamline sales activities.
• Things to note: The AI summarization feature is limited on the free plan.
• Things to note: It does not support recording offline meetings.

Pricing: Free (Unlimited recording and transcription) / Pro $29/month / Business $98/month / Enterprise (contact sales)

Best for: Those who want to automate online meeting records or improve workflow efficiency through CRM integrations. However, Japanese transcription accuracy is reportedly slightly lower than for English. If your meetings are primarily in Japanese, it is best to verify accuracy on the free plan before starting.

View detailed features, pricing, and FAQ for tl;dv

7. Fireflies.ai

Fireflies.ai is an AI-powered tool for automatic meeting recording, transcription, and summarization. It integrates with over 15 web conferencing platforms like Zoom and Teams to automatically generate meeting minutes. It supports over 100 languages, including Japanese transcription.

• Strengths: High-accuracy transcription supporting over 100 languages
• Strengths: Integrates with over 5,000 business tools, including CRMs and Slack
• Strengths: Speaker recognition allows for records created per speaker
• Things to note: The free plan limits AI summarization to 20 times per month
• Things to note: Transcription of meetings with mixed languages is only available on the Business plan or higher

Pricing: Free $0 (20 AI summaries/month) / Pro $10/user/month (annual billing) / Business $19/user/month (annual billing) / Enterprise $39/user/month

Best for: Sales teams or executive meetings that want to efficiently organize multilingual meeting content while leveraging CRM integrations. Note, however, that a notification is displayed when recording starts.

View detailed features, pricing, and FAQ for Fireflies.ai

8. Glasp

Glasp is a tool for saving and sharing highlights and notes from web pages, PDFs, and YouTube videos. AI features automatically extract key points from articles and summarize video subtitles. As a Japan-based service, it offers robust support for Japanese UI and content.

• Strengths: Intuitive operation that automatically saves text highlighted on the web
• Strengths: AI summarizes YouTube video subtitles, allowing you to grasp key points of long videos
• Strengths: Supports export to Notion and Readwise, plus social features that let you view highlights from other users
• Things to note: Only Chrome and Safari are supported; Firefox is not supported
• Things to note: No mobile app is available, so you must use the web version on smartphones

Pricing: Free (basic features) / Pro $12/month

Best for: Those who want to efficiently organize study notes from web articles and videos, as well as those who want to read or gather information while referencing others' highlights.

9. QuillBot Summarizer

QuillBot Summarizer is the summarization feature of QuillBot, known as an AI paraphrasing tool. It generates two patterns of summaries—short and long—from input text, allowing you to adjust detail level based on your needs. It integrates with features like paraphrasing and grammar checking, enabling one-stop writing workflows.

• Strengths: Integrates paraphrasing, grammar checking, and plagiarism checking.
• Strengths: Summarization up to 2,500 words is available on the free plan.
• Strengths: Works with Word and Google Docs, allowing direct use within documents.
• Things to note: Japanese summarization accuracy may be lower compared to English.
• Things to note: Compared to dedicated summarization tools, the summarization feature itself is simple.

Pricing: Free (summarize up to 2,500 words) / Premium $9.95/month ($49.95/year with annual billing; summarize up to 6,000 words)

Best for: Those who work mainly with English documents or want to summarize, rewrite, and grammar-check in one place. Japanese is partially supported, but it works best in English.

View detailed features, pricing, and FAQ for QuillBot Summarizer

10. Scholarcy

Scholarcy is an AI tool specialized in summarizing academic papers and research materials. When you upload a paper, the AI extracts key information such as research objectives and methods, organizing it into flashcards. It also features Robo-Highlighter to automatically highlight important sections and displays links to open-access versions of cited references.

• Strengths: Specialized in academic paper summarization, with support for flashcard generation and automatic extraction of figures and tables. Summaries can be exported in Word, Markdown, and PowerPoint formats (saving and exporting require the paid Scholarcy Library).
• Strengths: Browser extensions (Chrome, Edge, Firefox) are available for free. The Scholarcy Library plan is $4.99/month, an affordable price point for researchers.
• Things to note: Summarization accuracy for Japanese papers is low; use with English papers is recommended. Additionally, the interface is English-only, with no Japanese support.

Pricing: Browser extension Free / Scholarcy Library $4.99/month ($45/year with annual billing) / For educational institutions $8,000+/year

Best for: Researchers, graduate students, and undergraduates who read many English academic papers, especially for literature reviews and paper writing.

View detailed features, pricing, and FAQ for Scholarcy

Recommendations by Goal

Goal	Recommended	Reason
Want to try it for free first	Fathom, tl;dv	The free plan offers unlimited recording and transcription, allowing you to check features while keeping initial costs low.
Want to use it with Japanese text	Google NotebookLM, ChatPDF	They support Japanese UI and sources, enabling smooth understanding of long documents and PDFs.
Want to use it for work or teams	Otter.ai, Fireflies.ai	They integrate with meetings on Zoom or Teams, supporting speaker identification, action item extraction, and CRM integration (verify Japanese accuracy in advance).
Want to read academic papers efficiently	Scholarcy	Paper-focused, it creates flashcards and automatically highlights key sections, improving research efficiency.
Want to grasp key points of web articles or videos	Glasp, QuillBot Summarizer	They support saving highlights from web pages and YouTube, as well as generating flexible text summaries.
Want to prioritize security	Adobe Acrobat AI	It provides enterprise-grade security and offers high reliability in terms of compliance.

The above reflects general trends based on data. The optimal tool varies depending on specific workflows and organizational policies. We recommend using the free plan before implementation to confirm actual usability.

How to Choose Without Regrets

Clarify your purpose and target content

If you prioritize meeting transcription, Otter.ai or Fathom are suitable. On the other hand, if you aim to improve the efficiency of reading PDFs or web articles, consider ChatPDF or Google NotebookLM. Some tools, like Scholarcy, are specialized for academic papers and have limited scope. Confirm that the features align with your company's business workflows.

Pricing structure and free tier limits

The free plans of each tool have restrictions on usage counts, character limits, and so on. For example, Fathom offers unlimited recordings, while tl;dv has limits on AI summaries. The scope of what you can use for free varies by tool. Also, in cases like Adobe Acrobat AI, where AI feature add-on fees are charged on top of the base price, it is important to compare the total cost.

Japanese support accuracy and UI

Many tools support Japanese, but there are differences in transcription and summarization accuracy. Note that Otter.ai and Fathom only offer "partial" Japanese support, with lower accuracy compared to English. Also, Scholarcy has an English-only UI and is reported to have low summarization accuracy for Japanese papers. If your main use case involves working in Japanese, we recommend testing the tools to verify quality.

Platforms and integrations

Some tools work entirely within a web browser, while others require Chrome extensions or mobile apps. Glasp does not support Firefox and has no mobile app, but QuillBot Summarizer integrates with Word and Google Docs. Furthermore, some tools, like Fireflies.ai, integrate with over 5,000 apps. Check compatibility with your existing business systems.

Security and data management

For tools like Otter.ai and Fathom that store meeting content in the cloud, how audio data is handled is important. Adobe Acrobat AI claims enterprise-grade security but cannot be used in offline environments. Select a tool after reviewing your internal information security policies and regulations regarding sending data to external services.

FAQ

Q. Are there any free AI summarization tools?

Yes, several tools offer a free plan. Google NotebookLM provides basic features for free. Fathom allows unlimited recording, transcription, and AI summarization at no cost.

Also, tl;dv offers unlimited recording and transcription for free. However, the AI summarization feature is limited on tl;dv's free plan. ChatPDF and Otter.ai also have free tiers, but they impose limits on the number of files or usage time.

Q. Which tool is best for accurately summarizing Japanese meeting content?

Japanese support varies in accuracy across tools. tl;dv and Fireflies.ai support Japanese transcription and summarization. Otter.ai and Fathom also offer partial support, but accuracy may be lower compared to English.

In particular, if the audio quality of the meeting is poor, accuracy may drop with any tool. We recommend testing in your actual meeting environment for a final decision.

Q. Which tools are specialized for summarizing PDF files?

ChatPDF and Adobe Acrobat AI have strengths in PDF processing. With ChatPDF, you can upload a PDF and ask questions or get summaries in a conversational format. It displays the source page for citations, making it easy to verify content.

Adobe Acrobat AI offers powerful cross-PDF search and comparison features. However, using its AI features requires an additional subscription. If you want to focus on academic papers, Scholarcy is also an option.

Q. Are there any points to note regarding pricing plan differences?

Free plans often have limits on usage frequency or character count. For example, Otter.ai's free plan allows up to 600 minutes per month, while Fireflies.ai allows up to 20 AI summaries per month. ChatPDF's free plan is limited to 2 files per day, up to 120 pages each.

When moving to a paid plan, you need to check not only the monthly fee but also annual payment discounts and per-user billing methods. Please check the official website for the latest pricing and features.

Q. How can I choose a tool to avoid making a mistake?

It is important to choose a tool that fits your purpose. If your main goal is meeting transcription and summarization, Fathom or tl;dv are candidates. If you want to deepen your understanding of PDF documents, ChatPDF or Adobe Acrobat AI are suitable.

Also, check the supported browsers, operating systems, and required integrations (such as CRM or Slack). We recommend verifying Japanese accuracy and privacy policies in detail before implementation.

Summary

This article compared 10 AI summarization tools, including Google NotebookLM and ChatPDF. Each tool has different strengths; some excel at interactive questions about PDFs, while others specialize in meeting transcription. Pricing structures vary widely, with differences in the availability of free plans and monthly fees. It is important to choose based on your usage frequency.

You should also check the accuracy of Japanese support and platform compatibility. Some tools may have lower processing accuracy for Japanese compared to English, so judge them by actual user experience. Please check the official website for the latest pricing and features.

• In-depth understanding of PDFs → ChatPDF (easy to verify accuracy with source page citations)
• Automating meeting minutes → Fathom (unlimited recording and summarization available on the free plan)
• Reading academic papers → Scholarcy (grasp key points instantly with flashcard conversion)

View all AI summarization tools (14 items)