o3 vs Claude 3.5 Sonnet
Pricing, context window, and benchmark comparison · Last updated April 2026
Claude 3.5 Sonnet is cheaper than o3 at $3.00/1M/1M vs $10.00/1M/1M input tokens — a 3.3x cost difference. o3 scores higher on quality benchmarks (ELO 1380). Choose Claude 3.5 Sonnet for cost-sensitive workloads; choose o3 for maximum quality.
Which is cheaper: o3 or Claude 3.5 Sonnet?
Claude 3.5 Sonnet is the cheaper option at $3.00/1M per 1M input tokens, compared to $10.00/1M for o3. That is a 3.3x cost difference on input tokens. Output pricing follows a similar pattern: o3 charges $40.00/1M/1M vs $15.00/1M/1M for Claude 3.5 Sonnet.
Which has better quality: o3 or Claude 3.5 Sonnet?
Based on LMSYS Chatbot Arena rankings, o3 achieves a higher ELO score (1380 vs 1295), suggesting stronger performance on open-ended tasks. o3 excels at highest reasoning benchmark scores of any model. Claude 3.5 Sonnet is known for 200k context window — best for long documents.
Which should you choose: o3 or Claude 3.5 Sonnet?
- → Highest reasoning benchmark scores of any model
- → Better cost-efficiency than o1 at similar quality
- → Superior at agentic and multi-step tasks
- → 200K context window — best for long documents
- → Industry-leading coding performance
- → Nuanced instruction following
Frequently Asked Questions
Which is cheaper: o3 or Claude 3.5 Sonnet?
Claude 3.5 Sonnet is cheaper at $3.00/1M per 1M input tokens, making it 3.3x more affordable.
Which has better quality: o3 or Claude 3.5 Sonnet?
o3 scores higher on the LMSYS Chatbot Arena with an ELO of 1380, suggesting better overall quality for most tasks.
Which has a larger context window: o3 or Claude 3.5 Sonnet?
Both o3 and Claude 3.5 Sonnet have the same context window.
Should I choose o3 or Claude 3.5 Sonnet?
Choose Claude 3.5 Sonnet if cost is the priority. Choose o3 if benchmark quality is most important. Consider your specific use case: o3 is best for reasoning and math, while Claude 3.5 Sonnet excels at coding and document-analysis.
Is o3 or Claude 3.5 Sonnet open source?
o3 is proprietary. Claude 3.5 Sonnet is proprietary.