Claude Opus 5.5 vs GPT-6 Astra: which API costs less?
Averaged across three realistic workloads, Claude Opus 5.5 is about 62% cheaper than GPT-6 Astra. Below: raw rates and side-by-side monthly costs, computed from prices verified 2026-10-17 (we track what you are billed today, promos included).
Rates per 1M tokens
| Model | Input | Output | Cached input |
|---|---|---|---|
| Claude Opus 5.5Anthropic | $4 | $20 | $0.200 |
| GPT-6 AstraOpenAI | $10 | $50 | $1 |
Monthly cost, side by side
| Workload | Claude Opus 5.5 | GPT-6 Astra | Difference |
|---|---|---|---|
Customer-support chatbot 2M input + 0.5M output tokens/month, 60% of input served from prompt cache | $13.44 | $34.20 | Claude Opus 5.5 −61% |
RAG / document Q&A 20M input + 1M output tokens/month, 70% cached (shared context) | $46.80 | $124 | Claude Opus 5.5 −62% |
Agentic coding assistant 50M input + 5M output tokens/month, 80% cached (long sessions) | $148 | $390 | Claude Opus 5.5 −62% |
Your traffic looks different? Run your own numbers in the calculator.
FAQ
Which is cheaper: Claude Opus 5.5 or GPT-6 Astra?
Across three realistic workloads (chatbot, RAG, agent), Claude Opus 5.5 works out about 62% cheaper than GPT-6 Astra on average. Raw rates: Claude Opus 5.5 $4/$20 per 1M tokens vs GPT-6 Astra $10/$50. Verified 2026-10-17.
Does prompt caching change the comparison?
Yes — cached input costs $0.200 on Claude Opus 5.5 and $1 on GPT-6 Astra. Our scenario numbers already include realistic cache hit rates.
Is cheaper always better?
No. Price is one axis — model capability, context window and latency differ. This page answers only the cost question; benchmark quality on your own tasks before switching.