# Claude 4
Claude 4 is a generation of large language models released by [Anthropic](https://www.edgepedia.org/anthropic) on May 22, 2025, consisting at launch of [Claude Opus 4](https://www.edgepedia.org/claude-opus-4) and [Claude Sonnet 4](https://www.edgepedia.org/claude-sonnet-4), hybrid reasoning models that Anthropic positioned as leading coding models.[1](https://www.anthropic.com/news/claude-4) The release belongs to the Claude model family (covered separately), built by Anthropic, and underpins products such as Claude Code; this article covers the models themselves.
All benchmark figures below are vendor-reported by Anthropic. No independent third-party evaluation of any Claude 4 benchmark claim appears in the record as of September 2026, and Anthropic has not disclosed parameter counts for the 4.0 models.[1](https://www.anthropic.com/news/claude-4) • [2](https://intuitionlabs.ai/articles/anthropic-claude-4-llm-evolution)
| Fact | Value |
|---|---|
| Launch date | May 22, 2025 (Opus 4 and Sonnet 4)[1](https://www.anthropic.com/news/claude-4) |
| Headline coding scores (vendor) | Opus 4: 72.5% SWE-bench Verified, 43.2% Terminal-bench; Sonnet 4: 72.7% SWE-bench Verified[1](https://www.anthropic.com/news/claude-4) |
| Launch pricing | Opus 4 $15/$75 per million tokens (input/output); Sonnet 4 $3/$15[1](https://www.anthropic.com/news/claude-4) |
| Reasoning modes | Standard mode plus extended thinking up to 64K tokens; extended thinking with tool use in beta[1](https://www.anthropic.com/news/claude-4) |
| Safety levels | Opus 4 deployed under ASL-3, Sonnet 4 under ASL-2[3](https://www-cdn.anthropic.com/6d8a8055020700718b0c49369f60816ba2a7c285/Claude%204%20System%20Card.pdf) |
| Availability | Anthropic API, Amazon Bedrock, Google Cloud Vertex AI; Sonnet 4 also free for Claude free users[1](https://www.anthropic.com/news/claude-4) |
| Later line | Opus 4.1 (Aug 2025), Sonnet 4.5 (Sep 2025), Haiku 4.5 (Oct 2025), Opus 4.5 (Nov 24, 2025, $5/$25)[2](https://intuitionlabs.ai/articles/anthropic-claude-4-llm-evolution) |
## What Claude 4 is
Anthropic announced Claude Opus 4 and Claude Sonnet 4 on May 22, 2025, describing Opus 4 as its most powerful model and "the best coding model in the world."[1](https://www.anthropic.com/news/claude-4) Both models are hybrid reasoning models: they have an "extended thinking mode" in which they spend more time reasoning through problems, and a default standard mode for faster responses.[3](https://www-cdn.anthropic.com/6d8a8055020700718b0c49369f60816ba2a7c285/Claude%204%20System%20Card.pdf)
## Architecture and training as published
Anthropic disclosed the reasoning interface, not the underlying model. What is published: extended thinking can run up to 64K tokens, and extended thinking combined with tool use was offered in beta at launch.[1](https://www.anthropic.com/news/claude-4) Because full long reasoning traces are costly to display, a smaller model summarizes lengthier thought processes; only around 5% of thought processes are long enough to trigger summarization, and developers who need unsummarized traces can opt into a Developer Mode.[3](https://www-cdn.anthropic.com/6d8a8055020700718b0c49369f60816ba2a7c285/Claude%204%20System%20Card.pdf)
What is not published: the parameter count. A secondary account describes Claude 4 as building on the transformer-based architecture of its predecessors with larger-scale training and new system-level features, with no parameter count disclosed.[2](https://intuitionlabs.ai/articles/anthropic-claude-4-llm-evolution)
## Benchmarks: vendor claims and scoring caveats
At launch, Anthropic reported that Opus 4 scored 72.5% on SWE-bench Verified and 43.2% on Terminal-bench, while Sonnet 4 scored 72.7% on SWE-bench Verified, placing Sonnet 4 marginally above Opus 4 on that benchmark.[1](https://www.anthropic.com/news/claude-4) Without extended thinking, Opus 4 scored 74.9% on GPQA Diamond, 87.4% on MMMLU, 73.7% on MMMU, and 33.9% on AIME.[1](https://www.anthropic.com/news/claude-4) OSWorld and [ARC-AGI](https://www.edgepedia.org/arc-agi) scores are sometimes associated with this launch, but the sources in this record do not report them, so they are not stated here.
One scoring caveat matters for cross-vendor comparison. Anthropic disclosed that its [SWE-bench](https://www.edgepedia.org/swe-bench) scaffold used only a bash tool and a string-replacement file-editing tool, and that Claude 4 scores are reported out of the full 500 problems while OpenAI models are scored on a 477-problem subset.[1](https://www.anthropic.com/news/claude-4) Anthropic flagged this denominator difference itself; later cross-vendor tables, including secondary write-ups, present SWE-bench Verified percentages side by side without noting it.[2](https://intuitionlabs.ai/articles/anthropic-claude-4-llm-evolution) Readers comparing Claude 4's 72.5% with OpenAI's figures should keep the differing denominators in mind.
Anthropic also attributed the agentic gains partly to training against reward hacking: both models are, by its measurement, 65% less likely than Sonnet 3.7 to use shortcuts or loopholes on agentic tasks that are particularly susceptible to such behavior.[1](https://www.anthropic.com/news/claude-4)
## Pricing, availability and the 2025–2026 4.x timeline
Launch pricing was $15 per million input tokens and $75 per million output tokens for Opus 4, and $3/$15 for Sonnet 4, consistent with previous Opus and Sonnet pricing.[1](https://www.anthropic.com/news/claude-4) The models shipped on the Anthropic API, Amazon Bedrock, and Google Cloud's Vertex AI, and Sonnet 4 was also made available free to Claude free-tier users.[1](https://www.anthropic.com/news/claude-4) The record does not contain rate-limit details or a per-token price comparison with GPT-5, Gemini 2.5, or DeepSeek; only GPT-5's and [Gemini 3](https://www.edgepedia.org/gemini-3)'s release dates and a few scores appear.[2](https://intuitionlabs.ai/articles/anthropic-claude-4-llm-evolution)
Per a secondary account, the line then moved quickly:[2](https://intuitionlabs.ai/articles/anthropic-claude-4-llm-evolution)
- **Opus 4.1** (August 2025): an upgrade focused on agentic tasks, real-world coding, and reasoning.
- **Sonnet 4.5** (September 2025): introduced context awareness.
- **Haiku 4.5** (October 2025): the fastest and most cost-efficient model, achieving 90% of Sonnet 4.5's coding performance while running 4–5 times faster.
- **Opus 4.5** (November 24, 2025): reported at 80.9% SWE-bench Verified with a 67% price cut to $5/$25 per million tokens.
- By January 2026, Anthropic released Cowork, a graphical interface version of [Claude Code](https://www.edgepedia.org/claude-code) aimed at non-technical users, and Claude Code reached version 2.1.0.
For context on competitors, the same account dates OpenAI's GPT-5 to August 2025 with vendor-reported scores of 94.6% on AIME 2025 and 74.9% on SWE-bench Verified, and Google's Gemini 3 to November 2025 with Gemini 3 Flash in December 2025.[2](https://intuitionlabs.ai/articles/anthropic-claude-4-llm-evolution) These are vendor-reported figures from different scaffolds and, in GPT-5's case, a different SWE-bench denominator basis than Claude 4's launch disclosure.
## References
1. [Introducing Claude 4 — Anthropic](https://www.anthropic.com/news/claude-4)
2. [Anthropic Claude 4 LLM Evolution — IntuitionLabs](https://intuitionlabs.ai/articles/anthropic-claude-4-llm-evolution)
3. [System Card: Claude Opus 4 & Claude Sonnet 4 — Anthropic](https://www-cdn.anthropic.com/6d8a8055020700718b0c49369f60816ba2a7c285/Claude%204%20System%20Card.pdf)
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*Topic: Encyclopedia › Technology and the built world › Computing and digital systems › Modern AI: foundation models, generative AI, and the AI industry › Model families and named models › Large language model families › Proprietary model families*
*Initially written Sep 17, 2026 · Edited: Oct 11, 2026; Oct 15, 2026*
*Copyright 2026 EdgeChat AI, a subsidiary of Biostate AI.*
License: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license