GPT-5 excels in factual accuracy and coding benchmarks, while Claude 4 offers a larger context window and faster response times. GPT-5 is more cost-effective, but has demonstrated security vulnerabilities. Claude 4 provides robust multilingual capabilities and customization options.
| Attribute | Claude 4 | GPT-5 |
|---|---|---|
| Context Window Size | Up to 1 million tokens for Claude Sonnet 4, typically 200,000 tokens for Claude Opus 4 and Sonnet 4. Enterprise users can access 500,000 tokens with Sonnet 4. | ChatGPT: 8K tokens for Free, 32K for Plus, and 128K for Pro and Enterprise. API: Up to 400K tokens (272K input + 128K output). |
| Factual Accuracy | Claude 4 Sonnet incorporates feedback loops to minimize inaccuracies. | GPT-5 achieves an estimated 92.6% accuracy rate on standard benchmark tests. GPT-5 makes 80% fewer factual errors compared to previous models on benchmarks like LongFact and FactScore. |
| Reasoning Ability | Claude Opus 4 excels at complex problem-solving and delivers sustained performance on long-running tasks. 65% less likely to use shortcuts compared to earlier versions. | GPT-5 is designed for complex, multi-step workflows. It demonstrates strong results in math-heavy benchmarks. GPT-5 Thinking is configured to spend more time reasoning through complex prompts. GPT-5 Pro is designed for maximum reasoning depth and accuracy for research-grade tasks. |
| Coding Proficiency | Claude Opus 4 leads on benchmarks like SWE-bench (72.5%) and Terminal-bench (43.2%). Claude Sonnet 4 achieves 72.7% on SWE-bench. | GPT-5 scores 74.9% on SWE-bench Verified, a benchmark of real-world Python coding tasks. It excels at producing high-quality code and handling tasks such as fixing bugs, editing code, and answering questions about complex codebases. On Aider Polyglot, which tests multi-language code editing, GPT-5 reaches 88%. |
| Hallucination Rate | Claude Opus 4.1 has a hallucination rate of 4.2%, while Claude Sonnet 4 has a rate of 4.5%. | GPT-5 has a grounded hallucination rate of 1.4%. GPT-5's "thinking mode" has a significantly lower hallucination rate compared to previous models. On LongFact-Concepts and LongFact-Objects, GPT-5 records only 0.7% and 0.8% hallucinations, far below OpenAI o3. |
| Bias and Fairness | Claude 4 Opus leads with a bias score of 0.08. | Information about bias and fairness specifically was not found in the search results. |
| Safety and Security | Claude Opus 4 is released under stricter safety measures, known as AI Safety Level 3 (ASL-3). | GPT-5 introduces a new form of safety-training - safe completions - which teaches the model to give the most helpful answer where possible, while still maintaining safety boundaries. Cybersecurity researchers have demonstrated vulnerabilities in GPT-5, identifying methods to bypass its safety mechanisms and elicit harmful or undesired outputs. |
| Multilingual Support | Supports over 50 languages. | GPT-5's unified architecture brings a major leap in multilingual and voice capabilities. ChatGPT can now handle a wider range of languages with higher translation accuracy and fewer context drops across extended conversations. GPT-5 understands prompts in any language and generates content accordingly. |
| Customization Options | Users can establish persistent preferences, including preferred writing style and industry-specific terminology. Offers preset communication styles and the ability to upload writing samples. | Information about customization options specifically was not found in the search results. |
| API Availability and Pricing | Available on Anthropic API, Amazon Bedrock, and Google Cloud's Vertex AI. Claude Opus 4 is priced at $15 per million input tokens and $75 per million output tokens. Claude Sonnet 4 is priced at $3 per million input tokens and $15 per million output tokens. | GPT-5 is available in ChatGPT Pro and in the API. GPT-5 (Standard): $1.25/1M input, $10/1M output. GPT-5-mini: $0.25/1M input, $2/1M output. GPT-5-nano: $0.05/1M input, $0.40/1M output. |
| Speed and Latency | Offers near-instant responses and extended thinking for deeper reasoning. | GPT-5 (high) has a higher latency compared to average, taking 90.53s to receive the first token (TTFT). GPT-5 (high) has an output speed of 71.4 tokens per second, which is slower compared to average. |
| Memory and Long-Term Context Handling | Claude Opus 4 can create and maintain 'memory files' to store key information. | In ChatGPT, the model can hold around 256,000 tokens in memory; through the API, that expands to 400,000. GPT-5's improved tool intelligence lets it reliably chain together dozens of tool calls without losing its way. |