o3 vs Claude Sonnet 4.6
OpenAI's o3 against Anthropic's Claude Sonnet 4.6 — pricing, benchmarks, context, and best use cases compared side by side.
o3 and Claude Sonnet 4.6 are virtually tied on benchmark quality (Elo 1380 vs 1385), but o3 is 44% cheaper on blended cost. Claude Sonnet 4.6 offers a larger context window (1M vs 200K).
| Input Price | $2.00/1M | $3.00/1M |
| Output Price | $8.00/1M | $15.00/1M |
| Blended Price | $5.00/1M | $9.00/1M |
| LMSYS Elo | 1380 | 1385 |
| Context Window | 200,000 | 1,000,000 |
| Provider | OpenAI | Anthropic |
Pricing breakdown
When comparing LLM API pricing, o3 charges $2.00 per 1M input tokens compared to Claude Sonnet 4.6's $3.00 — a 33% difference. For output tokens, o3 costs $8.00/1M versus $15.00/1M for Claude Sonnet 4.6. On a blended basis (averaging input and output), o3 comes in at $5.00/1M tokens versus $9.00/1M for Claude Sonnet 4.6.
Quality & benchmarks
In terms of quality, o3 (Elo 1380) and Claude Sonnet 4.6 (Elo 1385) are essentially neck-and-neck on the LMSYS Chatbot Arena leaderboard. The 5-point gap is within the margin of uncertainty, meaning both models deliver comparable output quality for most use cases. Your choice between them should come down to pricing, ecosystem preferences, and specific feature needs rather than raw benchmark performance.
Context window comparison
Claude Sonnet 4.6 provides a significantly larger context window at 1M tokens compared to o3's 200K tokens — 5.0x more capacity for processing long documents, large codebases, or extended conversations. With 1M tokens, Claude Sonnet 4.6 can handle entire books, repositories, or multi-document analysis in a single prompt.
Monthly cost estimate
Adjust the sliders to see how costs compare for your workload.