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Claude Haiku 4.5 vs GPT-5.3 Codex
A detailed comparison of Claude Haiku 4.5 (Anthropic) and GPT-5.3 Codex (OpenAI) across pricing, performance, and features.
Pricing Comparison
| Metric | Claude Haiku 4.5 | GPT-5.3 Codex | Difference |
|---|---|---|---|
| Input / 1M tokens | $0.80 | $2.00 | +150% |
| Output / 1M tokens | $4.00 | $16.00 | +300% |
| Context window | 200K | 200K | — |
| Max output | 8.192K | 65.536K | — |
Benchmark Comparison
| Benchmark | Claude Haiku 4.5 | GPT-5.3 Codex |
|---|---|---|
| MMLU-Pro | 69.4% | 90% |
| HumanEval | 88.1% | 96.5% |
| GPQA | — | 78% |
Capabilities
| Capability | Claude Haiku 4.5 | GPT-5.3 Codex |
|---|---|---|
| code | ✓ | ✓ |
| reasoning | ✗ | ✓ |
| text | ✓ | ✓ |
| tool-use | ✓ | ✓ |
| vision | ✓ | ✓ |
Claude Haiku 4.5 Strengths
- ✓Very fast responses
- ✓Cheapest Anthropic option
- ✓Good for classification and extraction
Claude Haiku 4.5 Weaknesses
- ✗Weakest reasoning in the Claude family
- ✗Can struggle with nuanced instructions
GPT-5.3 Codex Strengths
- ✓Best coding model from OpenAI
- ✓Large output window (65K tokens)
- ✓Strong reasoning for complex tasks
GPT-5.3 Codex Weaknesses
- ✗API access not yet available
- ✗Premium pricing
Quick Verdict
Best value: Claude Haiku 4.5 is the more affordable option at $0.8/$4 per 1M tokens.
Higher benchmarks: GPT-5.3 Codex scores higher on average across available benchmarks (88.2% avg).
Choose Claude Haiku 4.5 if cost matters most. Choose GPT-5.3 Codex if you need the best possible quality for complex tasks.