Claude Opus 4.7 vs Claude Sonnet 5
Pricing, context window and real answers (August 2026)
Claude Opus 4.7 (Anthropic) and Claude Sonnet 5 (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 Opus 4.7 | Claude Sonnet 5 | |
|---|---|---|
| Provider | Anthropic | Anthropic |
| Input (per 1M tokens) | ¥840 | ¥357.4 |
| Output (per 1M tokens) | ¥4,200 | ¥1,787 |
| Typical cost (1,000 in + 500 out tokens × 1,000 calls) | ¥2,940 | ¥1,251 |
| Context window | 1,000,000 tokens | 1,000,000 tokens |
| Release date | 4/16/2026 | 6/30/2026 |
| Input modalities | text, image, file | text, image, file |
| Arena · overall | #6 · ELO 1,494 | #47 · ELO 1,461 |
| Arena · Japanese | #18 · ELO 1,478 | #33 · ELO 1,447 |
| Arena · coding | #4 · ELO 1,547 | #22 · ELO 1,522 |
Prices are FastMetal's yen rates before tax. Arena ranks are as of the latest leaderboard scrape.
Which should you pick?
- On price, Claude Sonnet 5: ¥1,787 per 1M output tokens, 57% less than Claude Opus 4.7.
- On the Overall arena board, Claude Opus 4.7 ranks higher (#6; Claude Sonnet 5 is #47).
- On the Japanese arena board, Claude Opus 4.7 ranks higher (#18; Claude Sonnet 5 is #33).
- On the Coding arena board, Claude Opus 4.7 ranks higher (#4; Claude Sonnet 5 is #22).
- 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 Claude Sonnet 5?
- Per 1M output tokens, Claude Opus 4.7 is ¥4,200 and Claude Sonnet 5 is ¥1,787 on FastMetal (yen, before tax), so Claude Sonnet 5 is cheaper.
- How do the context windows of Claude Opus 4.7 and Claude Sonnet 5 compare?
- Claude Opus 4.7 takes 1,000,000 tokens; Claude Sonnet 5 takes 1,000,000.
- Which ranks higher, Claude Opus 4.7 or Claude Sonnet 5?
- Claude Opus 4.7 ranks higher on the public arena (Claude Opus 4.7 #18, Claude Sonnet 5 #33). Ranks move as the leaderboard updates.
- Can I use Claude Opus 4.7 and Claude Sonnet 5 with the same API key?
- Yes. On FastMetal's OpenAI-compatible endpoint, switch by passing "anthropic-claude-opus-4-7" or "anthropic-claude-sonnet-5" 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 Claude Sonnet 5 from the browser chat and the API. No monthly fee.