Anthropic: Claude Sonnet 4.5 vs OpenAI: o3
On input price, OpenAI: o3 is ~1.5× cheaper. Verified 2026-08-23.
| Metric | Anthropic: Claude Sonnet 4.5 | OpenAI: o3 |
|---|---|---|
| Input / 1M | $3.00 | $2.00 |
| Output / 1M | $15.00 | $8.00 |
| Cache read / 1M | $0.300 | $0.500 |
| Context window | 1M | 200K |
| Max output | 64K | 100K |
Monthly cost by workload
| Workload | Anthropic: Claude Sonnet 4.5 | OpenAI: o3 | Cheaper |
|---|---|---|---|
| Chatbot | $84.00 | $48.00 | OpenAI: o3 |
| Coding agent | $270.00 | $160.00 | OpenAI: o3 |
| RAG pipeline | $585.00 | $360.00 | OpenAI: o3 |
Full details: Anthropic: Claude Sonnet 4.5 pricing · OpenAI: o3 pricing