New Generation of Models: Meet Claude 4 and GPT-5

The year 2026 is marked by significant improvements. OpenAI, after long anticipation, introduced the initial version of GPT-5, the successor to the groundbreaking GPT-4. Although full details are still shrouded in mystery, available information and API tests suggest a leap in multimodal reasoning – the model better understands and connects text, images, and now complex datasets. OpenAI has focused on improving logical inference and reducing the rate of "hallucinations," i.e., fabricating facts. On the other hand stands Claude 4 from Anthropic. It continues its philosophy focused on safety and reliability. Claude 4 comes with a massive context window, reportedly exceeding 500,000 tokens, allowing it to analyze entire books or extensive corporate documentation in a single query. Anthropic has also worked on a better understanding of the nuances of human language and ethical dilemmas, making it a strong player in areas where accuracy and safety are paramount.

Performance Comparison: Who Wins in Benchmarks?

Direct comparison of numbers is always tricky, but standardized tests give us a good picture of the capabilities of both models.

Academic and Standardized Tests

In tests like MMLU (a knowledge test across 57 different fields), GPT-5 maintains a slight lead, especially in exact sciences like mathematics and physics. Its ability to solve complex, multi-step problems is still top-notch. Claude 4, however, excels in tests focused on text comprehension, literary analysis, and in the humanities. According to independent analyses, it achieves better results in tests evaluating creative writing and summarizing complex texts.

"Popular" Vote: Chatbot Arena

An interesting perspective is offered by the LMSys Chatbot Arena project, where users blindly evaluate the responses of various models. Here, the results are often closer. While GPT-5 is often preferred for tasks requiring coding or precise logical deduction, Claude 4 gains fans thanks to its ability to conduct more natural, "human-like" conversations and generate more readable and stylistically richer texts.

Practical Implications for Users and Businesses in the Czech Republic

But what do these numbers mean for us in the Czech Republic?

Czech Language Support and Localization

Both models have made enormous progress in supporting the Czech language. GPT-5 still holds a slight advantage in grammatical correctness and understanding complex Czech compound sentences. Its training data clearly contained a massive amount of Czech text. Claude 4, however, has significantly improved and its responses are often stylistically more natural and less "robotic." For everyday conversation and content creation, both models are at an excellent level. However, neither of them yet has a fully localized interface or support specifically aimed at the Czech market.

Enterprise Deployment and Security

For businesses, reliability and security are key. Here, Anthropic with its Claude 4 has a slight edge. Their model is designed with an emphasis on "Constitutional AI," which is a set of principles that prevent the model from generating harmful, unethical, or dangerous content. This reduces the risk of misuse and facilitates deployment in sensitive areas such as finance or law. In the context of European legislation, especially the EU AI Act, this emphasis on security can be a key advantage for European companies. While GPT-5 is also equipped with robust security filters, it has historically been more susceptible to "jailbreaking," i.e., bypassing security restrictions.

Price and Availability: How Much Does Intelligence Cost?

Both models offer both free and paid versions.

• Basic version (free): Both providers offer limited access to their models for free. This usually involves older versions (e.g., GPT-4) with limits on the number of queries. It is sufficient for getting acquainted with the technology.
• Premium subscription: ChatGPT Plus (typically around 20 USD/month) and Claude Pro (similar price) provide access to the latest models (GPT-5, Claude 4), faster response times, and higher limits. Both services are available to Czech users with standard credit card payment.
• API for developers: API prices vary. Historically, OpenAI was slightly more expensive, but with the arrival of GPT-5, it introduced more competitive prices. Anthropic tries to attract developers with lower prices, especially for models with a huge context window, which is its main selling point.

Conclusion: There is No Single Winner, Only the Right Choice

Asking whether Claude 4 or GPT-5 is better is like asking whether a screwdriver or a hammer is better. Each tool excels at something different. Opt for GPT-5 if:

• You need top performance in programming, mathematics, and logical reasoning.
• You work with multimodal data (text and images).
• You require the highest possible accuracy across a wide range of fields.

Opt for Claude 4 if:

• You process very long documents, books, or codes.
• You place maximum emphasis on security, ethics, and risk minimization.
• You prefer a more natural, creative, and stylistically richer text output.

For Czech users and businesses, the great news is that competition between these two players is driving prices down and quality, including Czech language support, steeply up. 2026 is the year when we can choose top-tier AI precisely according to our needs.