// head_to_head
Claude Fable 5.1 vs Claude Sonnet 5
Published LiveBench scores across all seven categories, live list pricing, context windows, and the measured cost of a point of capability — for both models, side by side.
Claude Fable 5.1 scores higher, Claude Sonnet 5 costs less — it depends on your workload.
Claude Fable 5.1 is ahead by 7.4 points overall, and Claude Sonnet 5 lists 5.0× cheaper per blended million tokens. Whether 7.4 points is worth that depends on how much a wrong answer costs you. Claude Sonnet 5 also leads on measured cost per point of capability, at $0.2691 per point.
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Claude Fable 5.1
- Blended / 1M
- $20.00
- Context
- 1M
- Released
- Sep 1, 2026
- Overall score
- 83.4
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Claude Sonnet 5
- Blended / 1M
- $4.00
- Context
- 1M
- Released
- Jun 30, 2026
- Overall score
- 76.0
Specs and pricing
| Metric | Claude Fable 5.1 | Claude Sonnet 5 |
|---|---|---|
| LiveBench overall Mean of the seven LiveBench category scores, 0–100. Higher is better. | 83.4win | 76.0 |
| Cost per point Measured benchmark spend divided by overall score — dollars per point of capability. | $0.6668 | $0.2691win |
| Blended price / 1M 3:1 input:output mix, the usual shape of production traffic. | $20.00 | $4.00win |
| Input price / 1M | $10.00 | $2.00win |
| Output price / 1M | $50.00 | $10.00win |
| Cached input / 1M Price of an input token served from the prompt cache, where the provider publishes one. | $0.250 | $0.200win |
| Context window | 1M | 1M |
| Max output tokens | 128K | 128K |
Benchmarks by category
An overall score averages away the thing you probably care about. These are the seven LiveBench categories scored separately — Claude Fable 5.1 on top, Claude Sonnet 5 below, both out of 100.
What each one costs to run
Per-token prices are hard to feel. These are monthly list costs for both models across five workload shapes, using each provider's published cached-input rate where there is one.
| Workload | Claude Fable 5.1 | Claude Sonnet 5 |
|---|---|---|
| Support chatbot 1.2K in / 400 out × 200K requests | $5698.00/mo | $1150.40/mo |
| RAG assistant 8K in / 600 out × 100K requests | $7100.00/mo | $1480.00/mo |
| Coding agent 40K in / 4K out × 20K requests | $6540.00/mo | $1392.00/mo |
| Document extraction 20K in / 1.5K out × 50K requests | $13,263/mo | $2660.00/mo |
| Bulk classification 500 in / 20 out × 5M requests | $25,125/mo | $5100.00/mo |
Which should you pick?
You are running this at volume
Claude Sonnet 5
Lowest measured cost per point of capability at $0.2691 per point — the gap compounds with every request.
Quality matters more than the bill
Claude Fable 5.1
Highest overall LiveBench score of the two at 83.4.
The workload is coding or agentic work
Claude Fable 5.1
Leads on agentic coding — 66.1 against 59.4.
Claude Fable 5.1 vs Claude Sonnet 5 FAQ
Which is better, Claude Fable 5.1 or Claude Sonnet 5?
Claude Fable 5.1 scores higher, Claude Sonnet 5 costs less — it depends on your workload. Claude Fable 5.1 is ahead by 7.4 points overall, and Claude Sonnet 5 lists 5.0× cheaper per blended million tokens. Whether 7.4 points is worth that depends on how much a wrong answer costs you. Claude Sonnet 5 also leads on measured cost per point of capability, at $0.2691 per point.
Is Claude Fable 5.1 cheaper than Claude Sonnet 5?
Claude Sonnet 5 is cheaper. On a 3:1 input:output blend, Claude Fable 5.1 lists at $20.00 per million tokens and Claude Sonnet 5 at $4.00 — Claude Sonnet 5 is 5.0× cheaper. Input and output are priced separately — Claude Fable 5.1 charges $10.00 in and $50.00 out, Claude Sonnet 5 charges $2.00 and $10.00 — so the model that looks cheaper flips depending on how output-heavy your workload is.
Claude Fable 5.1 vs Claude Sonnet 5: which scores higher on benchmarks?
Claude Fable 5.1 scores 83.4 and Claude Sonnet 5 scores 76.0 overall on LiveBench, the mean of its seven categories. That is a 7.4-point lead for Claude Fable 5.1. Category scores differ from the overall figure — a model can lead on reasoning and trail on coding, which the per-category table above breaks out.
Which gives better value for money, Claude Fable 5.1 or Claude Sonnet 5?
Claude Sonnet 5. Cost per point divides the measured dollars LiveBench spent running the benchmark by the score it earned, so it captures something token pricing misses: a reasoning model can emit many times more tokens than its per-token rate suggests. Claude Fable 5.1 works out at $0.6668 per point and Claude Sonnet 5 at $0.2691.
Does Claude Fable 5.1 or Claude Sonnet 5 have a bigger context window?
They are effectively the same — 1M for Claude Fable 5.1 and 1M for Claude Sonnet 5.
Do Claude Fable 5.1 and Claude Sonnet 5 support prompt caching?
Both publish a cached-input rate: $0.250 per million for Claude Fable 5.1 and $0.200 for Claude Sonnet 5, against full input rates of $10.00 and $2.00. On a workload with a long stable prefix — a system prompt, a tool schema, a retrieved corpus — that changes the economics more than the headline price does.
Related comparisons
How these numbers are produced
- Price — provider list price from OpenRouter, refreshed every 15 minutes. “Blended” is a 3:1 input:output mix.
- Scores — LiveBench release 2026-06-25, using their own category map. Each model shows its strongest published run. A blank means “not evaluated”, never “bad”.
- Cost per point — the measured dollars LiveBench spent on the run, divided by the score it earned.
- “Win” — awarded only past a threshold: one full point on a benchmark score, 10% on a price, 25% on a context window. Anything tighter reports as a tie, because effort settings alone move a LiveBench score by more than that.
Published benchmarks rank models on someone else's tasks. Before committing, see LLM & agent evaluation for building an eval on your own.