Fast-mode variant of [Opus 5](/anthropic/claude-opus-5) - identical capabilities with higher output speed at 2x pricing relative to regular Opus 5. Learn more in Anthropic's docs: https://platform.claude.com/docs/en/build-with-claude/fast-…
Model details →Claude Opus 5 (Fast) vs OpenAI: GPT-4o (extended)
Claude Opus 5 (Fast) and OpenAI: GPT-4o (extended) are evenly matched on 6 axes — pick the one whose provider, latency, or licensing fits your stack.
GPT-4o ("o" for "omni") is OpenAI's latest AI model, supporting both text and image inputs with text outputs. It maintains the intelligence level of [GPT-4 Turbo](/models/openai/gpt-4-turbo) while being twice as fast and 50% more cost-effec…
Model details →Side-by-side comparison
| Capability | Claude Opus 5 (Fast) | OpenAI: GPT-4o (extended) | Winner |
|---|---|---|---|
| Context window Maximum number of input tokens the model can attend to in a single request. | 1M | 128K | 🏆 Claude Opus 5 (Fast) |
| Input price (per 1M) Cost per million input tokens billed by the provider. | $10.00 | $6.00 | 🏆 OpenAI: GPT-4o (extended) |
| Output price (per 1M) Cost per million output tokens billed by the provider. | $50.00 | $18.00 | 🏆 OpenAI: GPT-4o (extended) |
| Tool / function calling First-class support for emitting structured tool calls. | Yes | Yes | Tie |
| Vision input Accepts image inputs alongside text. | Yes | Yes | Tie |
| Reasoning mode Internal chain-of-thought / extended-thinking support. | Yes | — | 🏆 Claude Opus 5 (Fast) |
Frequently asked questions
Is Claude Opus 5 (Fast) better than OpenAI: GPT-4o (extended)?
Claude Opus 5 (Fast) and OpenAI: GPT-4o (extended) are evenly matched on 6 axes — pick the one whose provider, latency, or licensing fits your stack.
What's the price difference between Claude Opus 5 (Fast) and OpenAI: GPT-4o (extended)?
Input: $10.00 vs $6.00 per 1M tokens. Output: $50.00 vs $18.00 per 1M tokens.
What context windows do Claude Opus 5 (Fast) and OpenAI: GPT-4o (extended) support?
Claude Opus 5 (Fast) supports up to 1M tokens. OpenAI: GPT-4o (extended) supports up to 128K tokens.
Do both Claude Opus 5 (Fast) and OpenAI: GPT-4o (extended) support tool calling?
Claude Opus 5 (Fast): yes. OpenAI: GPT-4o (extended): yes.