Claude Opus 4.7 vs GPT-6 Astra
Pricing, context window and real answers (September 2026)
Claude Opus 4.7 (Anthropic) and GPT-6 Astra (OpenAI), compared as you can actually call them on FastMetal. Both are served from the same OpenAI-compatible endpoint and API key; switching is a change to the model string.
Specs and pricing
 Claude Opus 4.7 |  GPT-6 Astra | |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Input (per 1M tokens) | ¥840 | ¥1,717.72 |
| Output (per 1M tokens) | ¥4,200 | ¥8,588.62 |
| Typical cost (1,000 in + 500 out tokens × 1,000 calls) | ¥2,940 | ¥6,012 |
| Context window | 1,000,000 tokens | 1,050,000 tokens |
| Release date | 4/16/2026 | 9/4/2026 |
| Input modalities | text, image, file | file, image, text |
| Arena · overall | #7 · ELO 1,494 | Unranked |
| Arena · Japanese | #17 · ELO 1,478 | Unranked |
| Arena · coding | #4 · ELO 1,547 | Unranked |
Prices are FastMetal's yen rates before tax. Arena ranks are as of the latest leaderboard scrape.
Which should you pick?
- On price, Claude Opus 4.7: ¥4,200 per 1M output tokens, 51% less than GPT-6 Astra.
- For long documents, GPT-6 Astra: a 1,050,000-token context window against 1,000,000 for Claude Opus 4.7.
- If in doubt, try both on the same key. Switching is a change to the model string, and each is billed at its own rate.
Frequently asked questions
- Which is cheaper, Claude Opus 4.7 or GPT-6 Astra?
- Per 1M output tokens, Claude Opus 4.7 is ¥4,200 and GPT-6 Astra is ¥8,588.62 on FastMetal (yen, before tax), so Claude Opus 4.7 is cheaper.
- How do the context windows of Claude Opus 4.7 and GPT-6 Astra compare?
- Claude Opus 4.7 takes 1,000,000 tokens; GPT-6 Astra takes 1,050,000.
- Can I use Claude Opus 4.7 and GPT-6 Astra with the same API key?
- Yes. On FastMetal's OpenAI-compatible endpoint, switch by passing "anthropic-claude-opus-4-7" or "gpt-6-astra" as the model. Each is billed at its own rate from the same prepaid balance.
Try both on one API key
Create an account and add credit to call Claude Opus 4.7 and GPT-6 Astra from the browser chat and the API. No monthly fee.