# OpenAI o3 vs Claude Opus 4: which frontier reasoning model wins in 2026?

**Source:** https://promtable.com/compare/openai-o3-vs-claude-opus

> OpenAI o3 wins on math + competitive coding benchmarks, structured deliberation, and OpenAI ecosystem features. Claude Opus 4 wins on instruction following, long-form coding, tool use reliability, and extended thinking transparency. Pick o3 for math + code benchmarks, Opus 4 for real-world code + agent work.

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OpenAI o3 wins on math + competitive coding benchmarks, structured deliberation, and OpenAI ecosystem features. Claude Opus 4 wins on instruction following, long-form coding, tool use reliability, and extended thinking transparency. Pick o3 for math + code benchmarks, Opus 4 for real-world code + agent work.

## At a glance

| Dimension | OpenAI o3 | Claude Opus 4 |
|---|---|---|
| Math benchmarks | **Top tier** ✓ | Strong |
| Real-world code (SWE-bench) | Strong | **Top tier** ✓ |
| Instruction following | Strong | **Best in class** ✓ |
| Tool use / function calling | Strong | **Best in class** ✓ |
| Extended thinking visibility | Hidden reasoning + summary | **Visible thinking blocks (configurable)** ✓ |
| Multimodal | **Image + audio + video** ✓ | Image + video |
| Context window | ~200K | 200K + (extended for select tiers) |
| Pricing | Higher per output token | Similarly high reasoning tier |
| Best for | Math, competitive coding, structured deliberation | Real-world code, agent work, instruction-critical tasks |

## Verdict

OpenAI o3 is the right pick for math-heavy + competitive-coding tasks + structured deliberation chains where benchmark performance translates. Claude Opus 4 is the right pick for real-world coding + agent work + instruction-critical tasks — leads on SWE-bench, tool use reliability, and offers transparent extended thinking. Many production stacks route by task type: o3 for math / proofs / competitive code, Opus 4 for agentic code + multi-step reasoning + tool-heavy work.

## When to pick which

- **OpenAI o3** — Math, competitive coding, structured deliberation, OpenAI ecosystem.
- **Claude Opus 4** — Real-world code, agent work, instruction-critical tasks, visible thinking.

## FAQ

### Best for math?

OpenAI o3 — leads on math benchmarks.

### Best for real-world code?

Claude Opus 4 — leads SWE-bench + tool use reliability.

### Visible thinking?

Claude Opus 4 — extended thinking blocks are visible + configurable.

## Related

- [/compare/gpt-5-vs-claude-4-6](https://promtable.com/compare/gpt-5-vs-claude-4-6)
- [/compare/claude-vs-gpt-4o](https://promtable.com/compare/claude-vs-gpt-4o)
- [/glossary/extended-thinking](https://promtable.com/glossary/extended-thinking)
- [/glossary/test-time-compute](https://promtable.com/glossary/test-time-compute)

*Last updated: 2026-06-01*
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Original page: https://promtable.com/compare/openai-o3-vs-claude-opus
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