Claude Opus 5.5 vs Claude Fable 5.1: which should you use?
Prices, limits and measured figures for both models on Wokey, side by side. The data comes first, then when it points to Claude Opus 5.5 and when to Claude Fable 5.1.
Side by side
| Metric | Claude Opus 5.5 | Claude Fable 5.1 |
|---|---|---|
| Wokey input price (per 1M tokens) | $0.6 | $2.39 |
| Wokey output price (per 1M tokens) | $3 | $11.95 |
| Wokey cache read price | $0.03 | $0.0598 |
| Official price (input / output) | $4 / $20 | $10 / $50 |
| Context window | 1M | 1M |
| Max output | 128K | 128K |
| Image input | Yes | Yes |
| API forms | /v1/messages | /v1/messages |
| Time to first token, short prompts (median / p90) | 2.7 s / 13 s | 2.3 s / 11 s |
| Time to first token, large agent inputs (median) | 5.2 s | 6.9 s |
| Cache hit rate | 94.3% | 89.2% |
| Accounts in the sample | 900+ | 100+ |
When to use Claude Opus 5.5
- Budget matters or volume is high: Claude Opus 5.5 costs $0.6 input and $3 output per million tokens, against $2.39 and $11.95 for Claude Fable 5.1 — a 4× gap on output.
- You run agent tasks with long context: on large inputs the median time to first token is 5.2 s for Claude Opus 5.5 and 6.9 s for Claude Fable 5.1.
When to use Claude Fable 5.1
- You want the first token sooner: on short prompts the median time to first token is 2.3 s for Claude Fable 5.1 and 2.7 s for Claude Opus 5.5.
Where the data comes from
- Prices, context window, max output and API forms come from the Wokey model catalog, the same data billing uses.
- Time to first token and cache hit rate come from real requests through Wokey over a 28-day window; models without enough samples show no figure.
- Cache hit rate and time to first token depend on the client, prompt length and usage pattern. The two models have different users, so this is not a controlled test on the same requests.
FAQ
Which is cheaper, Claude Opus 5.5 or Claude Fable 5.1?
Claude Opus 5.5. On Wokey it costs $0.6 input and $3 output per million tokens; Claude Fable 5.1 costs $2.39 and $11.95.
Which responds faster, Claude Opus 5.5 or Claude Fable 5.1?
On real requests through Wokey, the median time to first token on short prompts is 2.3 s for Claude Fable 5.1 and 2.7 s for Claude Opus 5.5. This is time to first token, not the speed of the full response.
Can I switch between Claude Opus 5.5 and Claude Fable 5.1?
Yes. Both use the same Wokey API key and base URL: change the model ID in the request between claude-opus-5-5 and claude-fable-5-1, and each is billed at its own price.
Why is there no quality score here?
Wokey runs no benchmarks and gives no scores. This page holds only data we have ourselves: catalog prices and limits, and time to first token and cache hit rate measured on real requests. For quality, run your own task on both models.