text model comparison
Claude Fable 5.1 vs Claude Opus 5
Claude Fable 5.1 and Claude Opus 5 are both current text models, from Anthropic. Claude Opus 5 is 50% cheaper per 1M input tokens than Claude Fable 5.1, $5 vs $10. On Arena Text, Claude Fable 5.1 scores 1501 Elo and Claude Opus 5 1490 Elo (Arena, measured October 8, 2026). Both accept 1,000,000 tokens of context.
Data verified October 12, 2026 · Dataset 2026-10-13
Side by side
Prices in effect today, compared at the same tier wherever both list one. The better value in each row is highlighted.
| Fact | Claude Fable 5.1 | Claude Opus 5 |
|---|---|---|
| Price per 1M input tokens | $10 | $5 (better) |
| Price per 1M output tokens | $50 | $25 (better) |
| Arena Text | 1501 Elo (#4 of 49) (better) | 1490 Elo (#7 of 49) |
| FrontierMath Tiers 1-3 (v2) | 90.2% (#4 of 40) (better) | 85.6% (#10 of 40) |
| SimpleQA Verified | 70.8% (#5 of 36) (better) | 59.9% (#15 of 36) |
| GPQA Diamond | Not measured | 93.9% (#10 of 40) |
| Provider | Anthropic | Anthropic |
| Release date | September 1, 2026 | July 24, 2026 |
| Access | API only | API only |
| Context window | 1,000,000 tokens | 1,000,000 tokens |
| Max output | 128,000 tokens | 128,000 tokens |
| Input | text, image | text, image |
| Output | text | text |
What each costs
Example workloads at each provider's listed rates, then every other rate either one lists. The cheaper figure in each row is highlighted.
| Workload or rate | Claude Fable 5.1 | Claude Opus 5 |
|---|---|---|
| 10M input and 2M output tokens | $200 | $100 (better) |
| The same, with 9M of the input tokens cached | $112.25 | $59.50 (better) |
| The same, through the batch API | $100 | $50 (better) |
| Other listed rates | ||
| 1M input tokens, cached | $0.25 (better) | $0.50 |
| 1M input tokens, 5-minute cache write | $12.50 | Not listed |
| 1M input tokens, 1-hour cache write | $20 | Not listed |
| 1M input tokens, batch | $5 | $2.50 (better) |
| 1M output tokens, batch | $25 | $12.50 (better) |
When to choose each
Claude Fable 5.1
Where it leads
- Higher Arena Text score, 1501 Elo vs 1490 Elo
- Higher FrontierMath Tiers 1-3 (v2) score, 90.2% vs 85.6%
- Higher SimpleQA Verified score, 70.8% vs 59.9%
- Cheaper cached input, $0.25 vs $0.50 per 1M tokens
Best for
- Long-horizon agentic coding where a large prompt prefix is replayed across many turns
- Work where Claude Opus 5 at higher effort has already been evaluated and fell short
Watch out for
- Base input and output pricing is unchanged from Fable 5 at $10 / $50; the saving is entirely in cache reads, so a workload with little cache reuse sees no discount
- The 4.7-generation tokenizer produces roughly 30% more tokens for the same text than Claude Sonnet 4.6 and earlier, so per-token rates are not directly comparable across generations
- Anthropic’s launch comparisons are self-reported and were not reproduced independently here
Claude Opus 5
Where it leads
- Lower input and output prices, $5 and $25 vs $10 and $50 per 1M tokens
- Cheaper batch processing, $50 vs $100 for 10M input and 2M output tokens
Best for
- Complex agentic coding and enterprise work as the general-purpose default before reaching for Fable 5.1
- Latency-sensitive work that can justify Fast mode pricing
Watch out for
- Fast mode pricing applies to the whole request, including above 200K input tokens, so it doubles the effective rate rather than adding a surcharge
- Cache reads are $0.50 per million (the standard 0.1x), five times Fable 5.1’s $0.25, even though Opus 5 is the cheaper model on base tokens. A cache-heavy agent loop can invert the expected cost ordering between the two.
Claude Fable 5.1 vs Claude Opus 5 FAQ
Which is cheaper, Claude Fable 5.1 or Claude Opus 5?
Claude Opus 5 is 50% cheaper per 1M input tokens than Claude Fable 5.1, $5 vs $10. For 10M input and 2M output tokens, Claude Fable 5.1 costs $200 and Claude Opus 5 $100 at standard rates.
Which is cheaper with prompt caching, Claude Fable 5.1 or Claude Opus 5?
Claude Fable 5.1 charges $0.25 per 1M cached input tokens, 98% below its standard input rate, and Claude Opus 5 $0.50, 90% below. With 9M of 10M input tokens cached and 2M output tokens, Claude Fable 5.1 costs $112.25 and Claude Opus 5 $59.50.
Which scores higher on independent benchmarks, Claude Fable 5.1 or Claude Opus 5?
Claude Fable 5.1 leads on Arena Text, 1501 Elo to 1490 Elo; Claude Fable 5.1 leads on FrontierMath Tiers 1-3 (v2), 90.2% to 85.6%; Claude Fable 5.1 leads on SimpleQA Verified, 70.8% to 59.9%. Scores are independent evaluations, not either vendor's launch figures.
Which has the larger context window, Claude Fable 5.1 or Claude Opus 5?
Both accept 1,000,000 tokens of context. Both return up to 128,000 tokens per response.
Articles on Claude Fable 5.1 and Claude Opus 5
- Fable 5.1 vs Opus 5 vs GPT-5.6: Which to UseSeptember 1, 2026 · compares both
- Grok 4.7 vs Fable 5.1 vs GPT-6 Astra: Real Cost per TaskSeptember 23, 2026
- Jev vs Fable 5.1 vs GPT-6 Astra: Which Model for Which JobSeptember 22, 2026
- GPT-6 Astra vs Fable 5.1: Two Scoreboards, Two WinnersSeptember 22, 2026
- Claude Fable 5.1: Same Price, 75% Cheaper CacheSeptember 2, 2026
- Kimi K3 vs Opus 5 vs GPT-5.6 Sol: which model should you use?July 31, 2026
Related comparisons
- Claude Fable 5.1 vs Grok 4.7
- Claude Opus 5 vs Claude Opus 5.5
- Claude Fable 5.1 vs GPT-6 Astra
- Claude Opus 5 vs Gemini 3.8 Flash
- Claude Fable 5.1 vs Claude Opus 4.8
- Claude Opus 4.8 vs Claude Opus 5
- Claude Fable 5.1 vs GPT-5.6 Sol
- Claude Opus 5 vs Gemini 3.6 Flash
- Claude Fable 5 vs Claude Fable 5.1
- Claude Opus 5 vs GPT-5.5
- Claude Fable 5.1 vs Gemini 4 Argon
- Claude Opus 5 vs GPT-5.6 Sol
Production evaluation
Choosing between Claude Fable 5.1 and Claude Opus 5?
Public benchmarks narrow the shortlist. We run both on your own tasks, data and cost limits, then build the routing and review controls to run the winner in production.
- A head-to-head evaluation on your real workload
- Routing between models by cost and difficulty