Claude Sonnet 4.6 vs o3 for coding
o3 is the stronger coder of the two on benchmarks, but Claude Sonnet 4.6 can be the better pick when cost, speed, or context window matter more. Below: a side-by-side spec table and exactly when to pick each.
At a glance
| Spec | Claude Sonnet 4.6 | o3 |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Released | Sep 2025 | Apr 2025 |
| SWE-bench Verified | 64% | 71% |
| HumanEval | 92% | 96% |
| MMLU | 86% | 91% |
| Context window | 200K | 200K |
| Max output | 64K | 100K |
| Input price (per 1M) | $3 | $10 |
| Output price (per 1M) | $15 | $40 |
| Price tier | Mid | Premium |
| Speed | Standard | Slow/Reasoning |
| Hosting | Closed/API | Closed/API |
| Modality | Multimodal (vision) | Multimodal (vision) |
| Knowledge cutoff | Apr 2024 | Jun 2024 |
Pick Claude Sonnet 4.6 if…
- It's cheaper (Mid tier vs Premium).
- It responds faster (Standard).
- It's tuned for day-to-day coding, fast agentic loops, balanced cost/quality.
Pick o3 if…
- It scores higher on SWE-bench Verified (71% vs 64%), the best proxy for real-world coding.
- It's tuned for hardest coding problems, complex multi-step reasoning, advanced debugging.
Claude Sonnet 4.6 vs o3: which is better for coding?
o3 is the stronger coder of the two on benchmarks, but Claude Sonnet 4.6 can be the better pick when cost, speed, or context window matter more. See the full spec table for SWE-bench, HumanEval, MMLU, context window, and pricing on both. Benchmarks are a directional signal, not a guarantee for your codebase — the most reliable test is running both on a real task you care about.
Compare these head-to-head with live data, or build a full stack around your pick — Flowpicker shows compatibility and monthly cost.
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See the full model leaderboard ranked by SWE-bench, HumanEval, and MMLU.