Model comparison · Updated May 2026
Claude Sonnet 4.6 vs GPT-5.5: Price, Context, Benchmarks (2026)
A direct, dated comparison of Claude Sonnet 4.6 (Anthropic) and GPT-5.5 (OpenAI). Every number below is sourced from official provider docs and public benchmarks. If you need to make this decision today, the verdict is at the top.
30-second verdict
- Cheaper: Claude Sonnet 4.6 (input $3.00 vs $5.00 per 1M tokens).
- Longer context: GPT-5.5 at 1.1M vs 1M.
- Stronger on SWE-bench Verified: Claude Sonnet 4.6 (~70% vs ~65%).
- Higher LMArena: GPT-5.5 (1442 vs 1438).
Specs side-by-side
| Spec | Claude Sonnet 4.6 | GPT-5.5 |
|---|---|---|
| Vendor | Anthropic | OpenAI |
| Input price (per 1M tokens) | $3.00 | $5.00 |
| Output price | $15.00 | $30.00 |
| Context window | 1M | 1.1M |
| Release date | 2026-03-12 | 2026-04-23 |
| SWE-bench Verified | ~70% | ~65% |
| HumanEval | ~94% | ~96% |
| LMArena (approx) | 1438 | 1442 |
| Open weights | No | No |
| Capabilities | reasoning, code, vision | reasoning, code, vision |
Pricing from official Anthropic and OpenAI docs. Benchmark numbers from SWE-bench Verified, HumanEval, and LMArena public leaderboards as of May 2026.
Claude Sonnet 4.6 — strengths and weaknesses
Strengths. Best agentic coding, restrained edits, strong tool calling, default in Cursor / Cline / Aider.
Weaknesses. Pricier than DeepSeek; slower than Haiku tier.
Best for. Agentic coding, multi-file refactors, structured output, Cursor power-users.
GPT-5.5 — strengths and weaknesses
Strengths. Frontier reasoning, broad ecosystem, strong tool use, multimodal in/out.
Weaknesses. Premium pricing, occasional over-editing in agent loops.
Best for. Hard reasoning, ambiguous specs, system design, agent planners.
Which one should you pick?
Pick Claude Sonnet 4.6 if: agentic coding, multi-file refactors, structured output, cursor power-users.
Pick GPT-5.5 if: hard reasoning, ambiguous specs, system design, agent planners.
Use both if: you're building an agent or content pipeline. Route the high-stakes / hard-reasoning calls to whichever scores higher on the axis you care about, and the bulk / cheap calls to the other. Most production AI products run a 2-3 model router rather than betting on one.
Try them side-by-side
The Check.AI comparison tool lets you put both models in one table with all the numbers, switch capability filters, and share the resulting URL with your team.