Side-by-side comparison of pricing, context window, benchmarks, capabilities, and license. Data sourced from the Interestana AI Index, kept current as developers update their models.
Model A — Anthropic
Claude 4.5 Sonnet is Anthropic’s state-of-the-art coding and tool-use model, leading the SWE-bench coding benchmark and powering Claude Code, Claude.ai, and Claude in the Anthropic API.
Model B — OpenAI
o3 is OpenAI’s flagship reasoning model, scaling deliberate test-time compute to solve novel mathematics and science problems that earlier LLMs could not.
| Property | Claude 4.5 Sonnet | OpenAI o3 |
|---|---|---|
| Released | May 8, 2026 | Jan 31, 2026 |
| Developer | Anthropic | OpenAI |
| Type | multimodal | reasoning |
| License | proprietary | proprietary |
| Context window | 1,000,000 | 200,000 |
| Parameters | — | undisclosed |
| Input $/M tokens | $3.00 | $15.00 |
| Output $/M tokens | $15.00 | $60.00 |
Bold green values indicate the winner on that dimension where comparison is meaningful (lower price wins; bigger context wins; more open license wins; newer date wins).
| Benchmark | Claude 4.5 Sonnet | OpenAI o3 |
|---|---|---|
| GPQA Diamond | 79.8% | 87.7% |
Programmatic access available at /api/ai/compare?a=claude-4-5-sonnet&b=o3. CORS is open. Citation guidance: /about/editorial-process.