Claude 3 Sonnet vs GPT-5.3-Codex
Anthropic vs OpenAI — benchmarks, pricing, and capabilities side by side.
- •GPT-5.3-Codex has the higher intelligence index (91.5 vs 45.8)
- •GPT-5.3-Codex is cheaper ($1.75 vs $3.00 per 1M input)
- •Claude 3 Sonnet is faster
- •GPT-5.3-Codex has a larger context window (400K)
| Claude 3 Sonnet | GPT-5.3-Codex | |
|---|---|---|
| Intelligence index | 45.8 | 91.5 |
| Developer | Anthropic | OpenAI |
| Type | Multimodal | Multimodal |
| Access | API only | API only |
| Context window | 200,000 tokens | 400,000 tokens |
| Input price | $3.00 / 1M | $1.75 / 1M |
| Output price | $15.00 / 1M | $14.00 / 1M |
| Speed | 120 tok/s | 73 tok/s |
| Released | February 29, 2024 | February 24, 2026 |
| Parameters | — | — |
| Input modalities | — | Text, Image |
| Output modalities | — | Text |
Shared benchmarks
Claude 3 Sonnet
GPT-5.3-Codex
GPQA Diamond
40.4
91.5
Humanity’s Last Exam
3.8
39.9