Claude Opus 5.5 vs GPT-6 Astra: cost per task
Claude Opus 5.5 is cheaper on 13 of 14 tasks and about 1.4x cheaper on average (geometric mean). Claude Opus 5.5 has the higher LMArena Text score (1508 vs 1477).
| Task | Claude Opus 5.5 | GPT-6 Astra | Difference |
|---|---|---|---|
| Answer a chat question | 2.5¢ | 3.4¢ | 1.3x |
| Reply to a customer email | 0.79¢ | 0.89¢ | 1.1x |
| Write a 1,500-word blog post | 7.3¢ | 11¢ | 1.6x |
| Write 10 product descriptions | 8.8¢ | 6.2¢ | 1.4x |
| Translate 1,000 words | 5.1¢ | 8.0¢ | 1.6x |
| Proofread one page (500 words) | 2.2¢ | 4.0¢ | 1.8x |
| Summarize a 20-page PDF | 8.9¢ | 16¢ | 1.7x |
| Extract data from an invoice | 2.1¢ | 2.6¢ | 1.3x |
| Analyze a 200-row spreadsheet | 34¢ | 42¢ | 1.2x |
| Answer from 5 retrieved documents (RAG) | 5.5¢ | 5.9¢ | 1.1x |
| Classify 100 support tickets | 1.8¢ | 3.9¢ | 2.2x |
| Review 500 lines of code | 16¢ | 24¢ | 1.5x |
| Write a SQL query | 2.2¢ | 2.4¢ | 1.1x |
| Run a 50-step coding agent | $1.68 | $3.72 | 2.2x |
Specs and list prices
| Claude Opus 5.5 | GPT-6 Astra | |
|---|---|---|
| Input per 1M | $4.00 | $10.00 |
| Output per 1M | $20.00 | $50.00 |
| Cached input per 1M | $0.20 | $1.00 |
| Context | 1M | 1.05M |
| Providers | 11 | 7 |
| Reasoning | always | always |
| LMArena Text | 1508 | 1477 |
| Released | Sep 22, 2026 | Sep 4, 2026 |
FAQ
Is Claude Opus 5.5 or GPT-6 Astra cheaper?
Claude Opus 5.5 is cheaper on 13 of 14 tasks and about 1.4x cheaper on average (geometric mean). Claude Opus 5.5 has the higher LMArena Text score (1508 vs 1477).
How much does Claude Opus 5.5 cost compared to GPT-6 Astra per token?
Claude Opus 5.5: $4.00 input and $20.00 output per 1M tokens. GPT-6 Astra: $10.00 input and $50.00 output. Token prices alone mislead - models use different numbers of tokens for the same task, which is what the task table shows.