Claude Fable 5 vs Claude Opus 4.7
Pricing, context window and real answers (August 2026)
Claude Fable 5 (Anthropic) and Claude Opus 4.7 (Anthropic), 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 Fable 5 | Claude Opus 4.7 | |
|---|---|---|
| Provider | Anthropic | Anthropic |
| Input (per 1M tokens) | ¥1,787 | ¥840 |
| Output (per 1M tokens) | ¥8,935 | ¥4,200 |
| Typical cost (1,000 in + 500 out tokens × 1,000 calls) | ¥6,255 | ¥2,940 |
| Context window | 1,000,000 tokens | 1,000,000 tokens |
| Release date | 6/9/2026 | 4/16/2026 |
| Input modalities | text, image, file | text, image, file |
| Arena · overall | #1 · ELO 1,507 | #6 · ELO 1,494 |
| Arena · Japanese | #2 · ELO 1,526 | #18 · ELO 1,478 |
| Arena · coding | #3 · ELO 1,551 | #4 · ELO 1,547 |
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, 53% less than Claude Fable 5.
- On the Overall arena board, Claude Fable 5 ranks higher (#1; Claude Opus 4.7 is #6).
- On the Japanese arena board, Claude Fable 5 ranks higher (#2; Claude Opus 4.7 is #18).
- On the Coding arena board, Claude Fable 5 ranks higher (#3; Claude Opus 4.7 is #4).
- 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 Fable 5 or Claude Opus 4.7?
- Per 1M output tokens, Claude Fable 5 is ¥8,935 and Claude Opus 4.7 is ¥4,200 on FastMetal (yen, before tax), so Claude Opus 4.7 is cheaper.
- How do the context windows of Claude Fable 5 and Claude Opus 4.7 compare?
- Claude Fable 5 takes 1,000,000 tokens; Claude Opus 4.7 takes 1,000,000.
- Which ranks higher, Claude Fable 5 or Claude Opus 4.7?
- Claude Fable 5 ranks higher on the public arena (Claude Fable 5 #2, Claude Opus 4.7 #18). Ranks move as the leaderboard updates.
- Can I use Claude Fable 5 and Claude Opus 4.7 with the same API key?
- Yes. On FastMetal's OpenAI-compatible endpoint, switch by passing "anthropic-claude-fable-5" or "anthropic-claude-opus-4-7" 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 Fable 5 and Claude Opus 4.7 from the browser chat and the API. No monthly fee.