What is the difference between Claude and ChatGPT in 2026?
Claude is Anthropic’s AI assistant, and ChatGPT is OpenAI’s. Both search the web, both write fluent Danish, and both cost $20 per month on the standard paid plan. The difference lies in the model families, the user profile, and the way they select and display sources. At InboundCPH, we often get asked the question “Claude vs. ChatGPT”—both from people who need to choose a tool and from those who want to know if they’re mentioned in either one.
The models have different names, and those names change frequently. In September 2026, Anthropic will be selling the Mythos, Fable, Opus, Sonnet, and Haiku model families. The free Claude plan provides access to Sonnet and Haiku; the Pro plan unlocks Opus; and the Fable models are accessed using consumption credits. OpenAI runs the GPT-5.6 family with the Sol, Terra, and Luna variants, and GPT-6 Astra is being rolled out to Pro, Business, and Enterprise customers, according to OpenAI’s documentation from September 2026. For a Danish company, the names matter less than what they represent. Both offer a heavy-duty model for complex tasks, a mid-range model for everyday use, and a lightweight model for high-volume processing.
Prices are similar at the lower tiers. Claude Pro costs $20 per month, or $17 with annual billing, and Claude Max starts at $100 with five or twenty times the usage allowance. ChatGPT Plus costs $20, and ChatGPT Pro is available in two tiers at $100 and $200 per month. Both offer free plans with web search. These figures were taken from claude.com/pricing and OpenAI’s ChatGPT documentation on September 6, 2026, and may have changed by the time you read this.
| Claude (Anthropic) | ChatGPT (OpenAI) | |
|---|---|---|
| Model Families, Sept. 2026 | Myth, Fable, Opus, Sonnet, Haiku | GPT-5.6 Sol, Terra, and Luna; GPT-6 Astra on the way |
| Free Plan | Yes, with Sonnet, Haiku, and web search | Yes, using a web search |
| Standard Plan | Pro: $20/month ($17 with annual payment) | Plus: 20 USD/month. |
| Top Plan for Individuals | Max: starting at 100 USD/month (5x or 20x usage) | Pro: 100 USD/month (5x) or 200 USD/month (20x) |
| Team Schedule | Team: $20 per seat per month with annual payment | Business: per user/month. |
| Answers in Danish | Yes, you can | Yes, you can |
| Help Center in Danish | No (12 languages; Danish is not one of them) | Yes (help.openai.com/da-dk) |
The Danish language is not a problem for either of them. Both Claude and ChatGPT write in Danish at a level suitable for customer emails, analyses, and proposal texts. The difference lies outside the model itself: ChatGPT has a Danish help center and user interface, while Claude does not. For a department that needs to onboard 15 colleagues, this is a practical difference, not a difference in quality.
When do Claude and ChatGPT search the web, and how many sources do they cite?
Claude searches the web when the question depends on current or changing information, and draws on its training to provide answers based on stable knowledge. In practice, ChatGPT searches more frequently and typically cites more sources per answer. Both cite the pages they use with clickable links. That is the most important difference if you want to be evaluated based on whether your company is mentioned.
Anthropic describes the rule in its developer documentation. Claude performs searches for news, prices, statistics, information about specific companies and products, and when the user requests it. Claude responds without performing searches when dealing with established facts, code, creative writing, and analysis of material that the user has entered themselves. A simple factual question typically triggers 1 to 3 searches, while a comparison of multiple providers can trigger 10 or more. Web search has been enabled globally on all Claude plans since May 27, 2025. Anthropic has not disclosed which search index Claude uses, but documentation from February 2026 shows that Anthropic now also indexes content itself using the Claude-SearchBot.
ChatGPT has its own search tool and an index maintained by OpenAI itself. The OAI-SearchBot builds the index, and pages that have opted out of it appear only as navigation links and not as sources in the response. When we at InboundCPH tested the question “How does Claude choose its sources?” in ChatGPT on September 6, 2026, with a Danish location setting, the model ran 2 searches, evaluated 25 web addresses, and cited 3 domains in the final response: a Danish agency website, an international developer blog, and Anthropic’s own documentation. Google’s AI mode cited three sources in response to the same question, none of which were Danish. We see this pattern consistently across our measurements: AI responses typically mention three to five companies, regardless of how many pages the model has read.
The competition to be cited is therefore a competition for a limited number of spots. We’ll walk you through how ChatGPT selects them in the guide to Visibility in AI Search. Here, we focus on what makes Claude special: fewer searches, fewer sources, and a preference for pages that convey something specific.
How do you compare Claude and ChatGPT on 10 Danish business questions?
They compare Claude and ChatGPT by asking the same 10 questions with web search enabled in both and recording four pieces of information per response: whether the model performed a search, how many sources it cited, how many were Danish, and which companies were recommended. InboundCPH calls this procedure the InboundCPH Claude Test Protocol. Our platform currently measures Google AI summaries, AI mode, and ChatGPT automatically, while Claude is measured manually using the protocol. We do not publish figures that we have not measured, so there are no percentages for Claude listed here yet.
The questions cover the customer journey from information to decision—the same breakdown as in our platform: Information, Compare, Selection, and Decision. According to 6sense (2025), 94 % of B2B buyers use AI assistants in the purchasing process, so the questions should resemble those a buyer actually asks.
| Questions | Travel Phase | Why it's included |
|---|---|---|
| What are the rules for e-invoicing in Denmark in 2026? | Information | Forcing both to seek help: the rules are changing |
| Is AI SEO better than regular SEO? | Information | From InboundCPH's own portfolio, known ChatGPT behavior |
| How much does an interim CFO cost per month in Denmark? | Information | Price inquiries trigger a search on both sites |
| Which ERP system is suitable for a manufacturing company with 80 employees? | Compare | Comparison with Multiple Partial Searches |
| Which CRM system is best suited for a B2B company with 20 salespeople? | Compare | Tests that mention Danish retailers |
| How much does an AI-powered SEO campaign cost? | Compare | From InboundCPH's portfolio: a Danish pricing issue |
| Which accounting firms are recommended for medium-sized businesses? | Selection | Shortlist question: Who is mentioned by name? |
| Which leasing partner is best for company cars? | Selection | Testing the Effect of the “Best” Phrase on Source Selection |
| Which agency should we choose for Google Ads in Denmark? | Selection | Local shortlist; requires Danish sources |
| How much does it cost for a company to switch pension providers? | Decision | Close to the decision-making process, combining price and rules |
Ask the question exactly as it is in both assistants
Use the same wording, on the same day, with web search enabled in both Claude and ChatGPT. Do not write “search the web” in the prompt, because then you won’t be measuring the model’s own choice.
Save the entire answer and the list of sources
Copy the answer and all the links cited into a spreadsheet. A simple “yes” or “no” to the question “Were we mentioned?” isn’t enough when, in three months, you’ll have to explain what changed.
Write down the four goals for each answer
Whether the model was searched (yes/no), the number of cited sources, the number of Danish sources, and the names of companies mentioned in the response. Four columns per assistant result in eight figures per question.
Repeat after 30 days
Trends change, and your content evolves. Only the second measurement will show whether a new page has made a difference.
The example from the previous section illustrates what the protocol detects. In “How Does Claude Choose His Sources?”, ChatGPT read 25 pages and cited 3. Among the 25 were six guides to source criticism from Danish university libraries, which the model found via the word “sources” and subsequently rejected. You’ll only see that noise if you save the entire list of sources.
What does it take to be cited in Claude?
To be cited in Claude, three conditions must be met: the page must be accessible to Claude-SearchBot and Claude-User; it must answer the question precisely in the first sentence; and the sender must be unambiguous. InboundCPH checks these three layers in that order when a customer’s page does not appear in Claude’s response. The order is important because a problem in the first layer renders the next two irrelevant.
In short, the way it selects sources works the same as ChatGPT, just with fewer options. Claude assesses whether the question requires up-to-date knowledge, sends one or more search queries, retrieves the pages that look most promising, and extracts the passages that contain a specific answer. The passage is cited, not the page as a whole. That’s why a single sentence with numbers and units trumps three paragraphs about why AI is changing everything. In an analysis of 75,000 brands, Ahrefs found that brand mentions correlate about three times more strongly with AI visibility than backlinks (0.66 vs. 0.22). This aligns with what we see in the raw responses: the model cites pages that discuss named entities with numbers.
Claude-SearchBot and Claude-User can retrieve the page
Check your robots.txt file, CDN rules, and bot protection. A well-intentioned “block all AI bots” rule from 2024 often affects both types of bots. Without access, the content will never be considered.
The first sentence under each heading is the answer
Claude quotes passages. Include numbers with units, years, and sources in the visible text. State any reservations openly: “depending on the starting point” is easier to quote accurately than an unconditional promise.
Named author, clear organization, consistent facts
The same company name, the same address, and the same information about yourselves throughout the site and in trade publications. The model selects sources it can vouch for, and conflicting information about the sender undermines trust.
Claude is also reading your offers
Claude is primarily used to analyze documents that users upload themselves: reports, contracts, and proposals. Your content thus encounters Claude twice—as a web source and as an attachment to a decision. Write in a way that ensures your text can withstand critical review by a model: clear statements, figures, and disclaimers. This is the same standard we at InboundCPH follow when we write. AI-SEO Content for customers.
How do you add ClaudeBot, Claude-User, and Claude-SearchBot to robots.txt?
Anthropic uses three bots, each with its own user-agent name: ClaudeBot retrieves data for model training, Claude-User fetches pages on a user’s behalf, and Claude-SearchBot builds the search index. If you want to be cited in Claude, Claude-User and Claude-SearchBot must have access. If you block only ClaudeBot, you are opting out of training while maintaining your visibility. This breakdown is available in Anthropic's Help Center, last updated on April 7, 2026. The older name, Claude-Web, no longer appears in the documentation, and any rules related to it can be deleted.
OpenAI uses the same three-part structure. GPTBot fetches data for training, OAI-SearchBot builds the search index, and ChatGPT-User fetches pages when a user makes a query. OpenAI itself states that robots.txt rules do not necessarily apply to ChatGPT-User because the fetching is initiated by a human. A change to robots.txt takes effect in search results after about 24 hours. Anthropic supports the "Crawl-delay" directive to slow down the crawl and advises against blocking by IP address, as this prevents the bots from reading the robots.txt file at all.
| Purpose | Anthropic (Claude) | OpenAI (ChatGPT) | Effect of Blocking |
|---|---|---|---|
| Training Models | ClaudeBot | GPTBot | Future content is excluded from training. No effect on quotes |
| Search Index | Claude-SearchBot | OAI-SearchBot | The page disappears as a source in AI responses |
| Pickup for a user | Claude-User | ChatGPT User | The page cannot be accessed live. At OpenAI, robots.txt does not always apply |
| Advertise | None | OAI-AdsBot | Applies only to pages used as landing pages in ChatGPT Ads |
A robots.txt file that allows indexing but disallows crawling for both looks like this. Copy the block and customize it according to your own rules for other robots.
User-agent: ClaudeBot
Disallow: /
User-agent: GPTBot
Disallow: /
User-agent: Claude-SearchBot
Allow: /
User-agent: Claude-User
Allow: /
User-agent: OAI-SearchBot
Allow: /
User-agent: ChatGPT-User
Allow: /Training is a business decision, and there may be good reasons to say no. Search and user acquisition are visibility decisions, and for most B2B companies, the answer is yes. The basic rules for the file, including order and wildcard syntax, are outlined in our Guide to robots.txt. If ChatGPT is new to you, it offers Our ChatGPT Guide the basics before you go for your checkup.
Frequently Asked Questions About Claude and ChatGPT
Is Claude better than ChatGPT at Danish?
Both Claude and ChatGPT write fluent Danish, and InboundCPH has not observed any difference in the quality of responses to Danish business-related questions. The difference lies outside the model itself: ChatGPT has a Danish help center and user interface, while as of September 2026, Claude’s help center is available in 12 languages but not Danish. Choose based on how you work, not on language.
How much will Claude and ChatGPT cost in 2026?
Claude Pro costs $20 per month ($17 with annual billing), and Claude Max starts at $100. ChatGPT Plus costs $20, and ChatGPT Pro costs $100 or $200 per month, depending on usage. Both offer free plans with web search. Prices were obtained from Anthropic and OpenAI on September 6, 2026.
How does Claude search the web?
Claude determines on its own whether a question requires up-to-date information and only performs a search if that is the case. According to Anthropic’s documentation, a simple factual question triggers 1 to 3 searches, while a comparison can trigger 10 or more. Claude then fetches the pages, selects passages, and displays them as quotes with links. Web search has been available on all Claude plans since May 27, 2025.
Should I block ClaudeBot in robots.txt?
ClaudeBot only retrieves data for training Anthropic’s models. If you block it, it will not affect whether your pages are cited in Claude’s responses. Quotes depend on Claude-SearchBot and Claude-User, which Anthropic documented as separate bots in February 2026. If you want to opt out of training while maintaining visibility, block ClaudeBot and allow the other two.
Can InboundCPH measure our visibility in Claude?
In September 2026, InboundCPH’s AI visibility platform automatically measures Google AI summaries, AI mode, and ChatGPT, and saves the raw response for each question. We evaluate Claude manually using InboundCPH’s Claude test protocol, which consists of 10 questions and four metrics per response. The results are included in the AI visibility analysis alongside the automated measurements.
See what Claude and ChatGPT have to say about you
An AI visibility analysis shows you exactly what ChatGPT and Google AI respond with when your customers ask questions, and who is recommended instead of you. We evaluate Claude using the test protocol from this article. You’ll get the raw response behind each number.
Sources
- Anthropic: Plans & Pricing (accessed September 6, 2026)
- Anthropic: Web search tool—when Claude searches (2026)
- Anthropic: Claude can now search the web (March 20, 2025; globally at all levels, May 27, 2025)
- Anthropic: ClaudeBot, Claude-User, and Claude-SearchBot (April 7, 2026)
- OpenAI: ChatGPT Plans, GPT-5.6 Sol, Terra, and Luna, GPT-6 Astra (September 2026)
- OpenAI: Overview of OpenAI Crawlers (2026)
- OpenAI: Web Search in ChatGPT (2026)
- 6sense: Study of B2B Buyers' Use of AI Assistants (2025). Ahrefs: Analysis of 75,000 Brands: Brand Mentions vs. Backlinks
- InboundCPH AI-SEO Tools: Analysis of “How Does Claude Choose Its Sources?” in ChatGPT (gpt-5.6-luna) and Google AI Mode, September 6, 2026
Last revised on September 6, 2026. This article is reviewed on an ongoing basis whenever Anthropic and OpenAI update their models, pricing, or crawler documentation.
