Claude Fable 5.1 vs Claude Fable 5.2
Claude Fable 5.2 leads Claude Fable 5.1 on coding, 87.8 to 82.8 on the Vibe Coding Index, and Claude Fable 5.2 costs 1.3x less per output token ($40.00 vs $50.00 per million). Updated November 14, 2026; 63 benchmarks have a result for both.
vs boards won of 63 shared, 1 tied
Claude Fable 5.1 or Claude Fable 5.2: which to pick
Pick Claude Fable 5.2 for coding: it scores 87.8 on the Vibe Coding Index against 82.8 for Claude Fable 5.1, though on 4 benchmarks against 5.
Pick Claude Fable 5.1 for work measured by LiveBench coding or LiveBench browser, where it leads.
Model AClaude Fable 5.1Anthropic82.8/1005 independent benchmarksNo cost per solved taskModel BClaude Fable 5.2Anthropic87.8/1004 independent benchmarksNo cost per solved task
- Shared results
- 63
- Claude Fable 5.1 only
- 85
- Claude Fable 5.2 only
- 5
- Like-for-like categories
- 8 of 9
Only benchmarks that tested both models count toward a pick; a result only one model has is shown but not compared.
Which one for your work
Each card is decided by one number both models carry. Where only one has it, the card says so and makes no call.
Coding
Vibe Coding Index, six public coding benchmarks
Claude Fable 5.2
Claude Fable 5.2 scores 87.8 against 82.8.
5 and 4 benchmarks behind the scores
Intelligence
AA Intelligence Index
Claude Fable 5.2
Claude Fable 5.2 leads, 64.6 against 50.0.
Same board, both measured
Agentic work
AA Agentic Index
No call
Only Claude Fable 5.1 has a AA Agentic Index result, 57.2.
Directional only
Reasoning
GPQA Diamond
No call
Only Claude Fable 5.1 has a GPQA Diamond result, 93.4%.
Directional only
Knowledge
MMLU Pro
No call
Only Claude Fable 5.1 has a MMLU Pro result, 92.4%.
Directional only
Web design
Design Arena: websites
Claude Fable 5.2
Claude Fable 5.2 leads, 1351 against 1305.
Same board, both measured
General
Vals Index
No call
Only Claude Fable 5.2 has a Vals Index result, 71.3%.
Directional only
Long documents
Listed context window
No call
Both take 1M tokens.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Claude Fable 5.2
Claude Fable 5.1 $0.035, Claude Fable 5.2 $0.028 per turn.
List prices
At a glance
- Coding index
- Claude Fable 5.1 82.8 from 5 benchmarks, Claude Fable 5.2 87.8 from 4 benchmarks.
- Widest category
- Reasoning, 15.4 points apart on average over 13 shared benchmarks.
- Widest single gap
- EBR-bench: Claude Fable 5.1 57.1% against Claude Fable 5.2 90.5%, 33.3 points apart on a 0 to 100 scale.
- Output price
- Claude Fable 5.1 $50.00 against Claude Fable 5.2 $40.00 per million output tokens, 1.3x apart.
- Context window
- Both take 1M tokens.
Benchmark by benchmark
First the score: boards each model leads, per category, where both have a result. Then every board, a category to a fold; bars are each result on a 0 to 100 scale, so compare the two in a row, not one row with another.
| Category | Claude Fable 5.1 | Bars | Claude Fable 5.2 | Ties |
|---|---|---|---|---|
| Coding | 1 | 14 | ||
| Intelligence | 0 | 2 | ||
| Agentic work | 3 | 9 | ||
| Reasoning | 1 | 12 | ||
| Math | 1 | 3 | 1 tie | |
| Knowledge | 2 | 2 | ||
| Web design | 0 | 6 | ||
| General | 1 | 5 | ||
| All shared boards | 9 | 53 | 1 tie |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index114
| Benchmark | Claude Fable 5.1 | Claude Fable 5.2 | Leader |
|---|---|---|---|
| LiveBench coding | 89.7% | 79.2% | Claude Fable 5.1 |
| LMArena WebDev | 1742 | 1838 | Claude Fable 5.2 |
| AA Coding Index | 80.7 | Not measured | Only Claude Fable 5.1 measured |
| LiveCodeBench (Vals AI) | 90.5% | Not measured | Only Claude Fable 5.1 measured |
| Terminal-Bench 4 (Vals AI) | 58.1% | 65.2% | Claude Fable 5.2 |
| Vibe Code Bench (Vals AI) | 90.3% | 93.8% | Claude Fable 5.2 |
| Code migration (Vals AI) | 54.6% | Not measured | Only Claude Fable 5.1 measured |
| ProgramBench (Vals AI) | 7.0% | 19.0% | Claude Fable 5.2 |
| IOI (Vals AI) | 90.8% | Not measured | Only Claude Fable 5.1 measured |
| Terminal-Bench 2.1 (Vals AI) | 85.0% | Not measured | Only Claude Fable 5.1 measured |
| SWE-bench Multimodal (Vals AI) | 61.3% | 62.3% | Claude Fable 5.2 |
| Vibe Code Bench 1-100 (Vals AI) | 28.0% | Not measured | Only Claude Fable 5.1 measured |
| SkillsBench (Vals AI) | 61.5% | Not measured | Only Claude Fable 5.1 measured |
| CyberBench (Vals AI) | 70.4% | Not measured | Only Claude Fable 5.1 measured |
| SciCode | 63.1% | 67.7% | Claude Fable 5.2 |
| Terminal-Bench 4.0 (Artificial Analysis run) | 55.1% | 61.6% | Claude Fable 5.2 |
| FrontierCode 2.0 | 35.7% | 49.1% | Claude Fable 5.2 |
| FrontierCode | 50.9% | Not measured | Only Claude Fable 5.1 measured |
| FrontierSWE | 56.3% | 69.9% | Claude Fable 5.2 |
| GSO-Bench | 88.2% | Not measured | Only Claude Fable 5.1 measured |
| WeirdML | 92.9% | Not measured | Only Claude Fable 5.1 measured |
| MirrorCode | 93.3% | Not measured | Only Claude Fable 5.1 measured |
| ALE-Bench | 2143.2 | 2509.8 | Claude Fable 5.2 |
| LMArena Text: coding | 1527 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Text: software and IT | 1525 | Not measured | Only Claude Fable 5.1 measured |
| LMArena WebDev: React | 1787 | 1915 | Claude Fable 5.2 |
| LMArena WebDev: HTML | 1681 | 1738 | Claude Fable 5.2 |
| LMArena WebDev: from an image | 1724 | Not measured | Only Claude Fable 5.1 measured |
| SWE-Bench Pro V2 | 99.1% | Not measured | Only Claude Fable 5.1 measured |
| SWE Atlas: Codebase QnA | 60.0% | Not measured | Only Claude Fable 5.1 measured |
| SWE Atlas: Refactoring | 56.7% | Not measured | Only Claude Fable 5.1 measured |
| SWE Atlas: Test Writing | 67.0% | Not measured | Only Claude Fable 5.1 measured |
| GameBench 2 | 94.0 | 99.1 | Claude Fable 5.2 |
| Terminal-Bench 4.0 | 57.9% | Not measured | Only Claude Fable 5.1 measured |
| CursorBench 4.0 | 51.8% | 60.0% | Claude Fable 5.2 |
| ProgramBench | 9.0% | Not measured | Only Claude Fable 5.1 measured |
| Neither model has a result on the other 16 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index02
| Benchmark | Claude Fable 5.1 | Claude Fable 5.2 | Leader |
|---|---|---|---|
| AA Intelligence Index | 50.0 | 64.6 | Claude Fable 5.2 |
| Epoch Capabilities Index | 167.0 | 173.4 | Claude Fable 5.2 |
Agentic workLike-for-likePublic boards, shown as published, kept out of the index39
| Benchmark | Claude Fable 5.1 | Claude Fable 5.2 | Leader |
|---|---|---|---|
| AA Agentic Index | 57.2 | Not measured | Only Claude Fable 5.1 measured |
| Design Arena: agents building web apps | 1315 | Not measured | Only Claude Fable 5.1 measured |
| Design Arena: agents building full-stack apps | 1301 | 1402 | Claude Fable 5.2 |
| Design Arena: agents building mobile apps | 1253 | 1325 | Claude Fable 5.2 |
| Design Arena: agents building Godot games | 1304 | Not measured | Only Claude Fable 5.1 measured |
| Design Arena: HTML slides | 1390 | Not measured | Only Claude Fable 5.1 measured |
| Design Arena: PowerPoint slides | 1316 | Not measured | Only Claude Fable 5.1 measured |
| Design Arena: spreadsheets | 1346 | 1434 | Claude Fable 5.2 |
| LiveBench research | 88.5% | 94.5% | Claude Fable 5.2 |
| LiveBench browser | 89.8% | 86.9% | Claude Fable 5.1 |
| LiveBench long agentic | 74.2% | 82.9% | Claude Fable 5.2 |
| SREBench (Vals AI) | 22.9% | Not measured | Only Claude Fable 5.1 measured |
| Finance Agent (Vals AI) | 58.9% | Not measured | Only Claude Fable 5.1 measured |
| Tax Agent Bench (Vals AI) | 50.7% | 32.1% | Claude Fable 5.1 |
| Legal Research Bench (Vals AI) | 55.3% | 46.1% | Claude Fable 5.1 |
| Harvey's Legal Agent Benchmark (Vals AI) | Not measured | 5.0% | Only Claude Fable 5.2 measured |
| Excel Modeling Benchmark (Vals AI) | 76.7% | Not measured | Only Claude Fable 5.1 measured |
| BioMysteryBench (Vals AI) | Not measured | 83.7% | Only Claude Fable 5.2 measured |
| Terminal-Bench-Science (Vals AI) | 40.0% | 55.7% | Claude Fable 5.2 |
| Vals Science Index | Not measured | 63.7% | Only Claude Fable 5.2 measured |
| Time Horizon Index (Vals AI) | 63.3% | Not measured | Only Claude Fable 5.1 measured |
| CUA-bench (Vals AI) | 13.2% | Not measured | Only Claude Fable 5.1 measured |
| Robo-bench (Vals AI) | 5.8% | Not measured | Only Claude Fable 5.1 measured |
| APEX-Agents | 68.6% | 80.1% | Claude Fable 5.2 |
| Remote Labor Index | 17.9% | 41.3% | Claude Fable 5.2 |
| PostTrainBench | 44.6% | Not measured | Only Claude Fable 5.1 measured |
| SpireClimb | 2.0% | 15.5% | Claude Fable 5.2 |
| Vending-Bench 2 | $5,422 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Search | 1237 | Not measured | Only Claude Fable 5.1 measured |
| MCP Atlas | 87.2% | Not measured | Only Claude Fable 5.1 measured |
| Neither model has a result on the other 14 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index112
| Benchmark | Claude Fable 5.1 | Claude Fable 5.2 | Leader |
|---|---|---|---|
| GPQA Diamond | 93.4% | Not measured | Only Claude Fable 5.1 measured |
| LiveBench reasoning | 91.7% | 88.8% | Claude Fable 5.1 |
| MysteryMechanism (Vals AI) | 47.8% | 51.8% | Claude Fable 5.2 |
| MMMU Pro (Vals AI) | 90.6% | Not measured | Only Claude Fable 5.1 measured |
| GPQA Diamond (Artificial Analysis run) | 93.7% | Not measured | Only Claude Fable 5.1 measured |
| Humanity's Last Exam (Artificial Analysis run) | 59.1% | 74.3% | Claude Fable 5.2 |
| HLE-Diamond (Artificial Analysis run) | 60.1% | 80.2% | Claude Fable 5.2 |
| CritPt v2, hard subset (Artificial Analysis run) | 62.0% | 76.5% | Claude Fable 5.2 |
| GPQA Diamond (Epoch AI run) | Not measured | 93.9% | Only Claude Fable 5.2 measured |
| ARC-AGI | 97.5% | 98.5% | Claude Fable 5.2 |
| ARC-AGI-2 | 90.0% | 93.8% | Claude Fable 5.2 |
| SimpleBench | 86.6% | 94.9% | Claude Fable 5.2 |
| Chess puzzles | 48.0% | 79.0% | Claude Fable 5.2 |
| Mystery game puzzles | 58.0% | 90.0% | Claude Fable 5.2 |
| EBR-bench | 57.1% | 90.5% | Claude Fable 5.2 |
| LMArena Text: hard prompts | 1527 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Text: expert | 1546 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Text: hard prompts in English | 1522 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Vision: diagrams | 1346 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Vision: homework | 1339 | Not measured | Only Claude Fable 5.1 measured |
| Humanity's Last Exam (Scale run) | 51.3% | 72.4% | Claude Fable 5.2 |
| GoBench | 2268 | 2566 | Claude Fable 5.2 |
| Neither model has a result on the other 4 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index13
| Benchmark | Claude Fable 5.1 | Claude Fable 5.2 | Leader |
|---|---|---|---|
| OTIS Mock AIME | 100.0% | 99.7% | Claude Fable 5.1 |
| FrontierMath, tiers 1 to 3 | 90.2% | 95.1% | Claude Fable 5.2 |
| FrontierMath, tier 4 | 87.8% | 100.0% | Claude Fable 5.2 |
| ProofBench | 100.0% | 100.0% | Tie |
| LMArena Text: math | 1530 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Text: mathematical work | 1542 | Not measured | Only Claude Fable 5.1 measured |
| MathArena | 73.6% | 82.8% | Claude Fable 5.2 |
| Neither model has a result on the other 7 boards here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index22
| Benchmark | Claude Fable 5.1 | Claude Fable 5.2 | Leader |
|---|---|---|---|
| MMLU Pro | 92.4% | Not measured | Only Claude Fable 5.1 measured |
| LegalBench (Vals AI) | 88.5% | Not measured | Only Claude Fable 5.1 measured |
| TaxEval (Vals AI) | 76.0% | Not measured | Only Claude Fable 5.1 measured |
| MortgageTax (Vals AI) | 70.8% | Not measured | Only Claude Fable 5.1 measured |
| MedCode (Vals AI) | 53.5% | Not measured | Only Claude Fable 5.1 measured |
| AA-Omniscience | 46.3 | 66.8 | Claude Fable 5.2 |
| SimpleQA Verified | 70.8% | 94.0% | Claude Fable 5.2 |
| GeoBench | 84.0% | Not measured | Only Claude Fable 5.1 measured |
| LMArena Text: science | 1535 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Text: medicine and healthcare | 1529 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Text: legal and government | 1516 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Text: business and finance | 1494 | Not measured | Only Claude Fable 5.1 measured |
| PRBench Finance | 50.8% | 47.1% | Claude Fable 5.1 |
| PRBench Legal | 51.6% | 49.0% | Claude Fable 5.1 |
| Neither model has a result on the other 7 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index06
| Benchmark | Claude Fable 5.1 | Claude Fable 5.2 | Leader |
|---|---|---|---|
| Design Arena: websites | 1305 | 1351 | Claude Fable 5.2 |
| Design Arena: UI components | 1332 | 1371 | Claude Fable 5.2 |
| Design Arena: game dev | 1364 | 1396 | Claude Fable 5.2 |
| Design Arena: data viz | 1345 | Not measured | Only Claude Fable 5.1 measured |
| Design Arena: 3D | 1387 | 1517 | Claude Fable 5.2 |
| Design Arena: all code categories | 1330 | 1373 | Claude Fable 5.2 |
| Design Arena: SVG | 1292 | Not measured | Only Claude Fable 5.1 measured |
| Design Arena: ASCII art | 1318 | Not measured | Only Claude Fable 5.1 measured |
| LiveBench design | 81.6% | 85.1% | Claude Fable 5.2 |
GeneralLike-for-likePublic boards, shown as published, kept out of the index15
| Benchmark | Claude Fable 5.1 | Claude Fable 5.2 | Leader |
|---|---|---|---|
| Vals Index | Not measured | 71.3% | Only Claude Fable 5.2 measured |
| LiveBench data analysis | 80.3% | 81.5% | Claude Fable 5.2 |
| Public Benefits Bench (Vals AI) | 74.9% | Not measured | Only Claude Fable 5.1 measured |
| MedScribe (Vals AI) | 91.3% | Not measured | Only Claude Fable 5.1 measured |
| Long context reasoning (AA-LCR) | 85.3% | 83.3% | Claude Fable 5.1 |
| GDPval-AA | 1765 | 1831 | Claude Fable 5.2 |
| DTBench | 97.6% | 99.2% | Claude Fable 5.2 |
| LMCA | 65.5% | 70.6% | Claude Fable 5.2 |
| Furniture assembly | 70.0% | 90.0% | Claude Fable 5.2 |
| LMArena Text | 1512 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Text: instruction following | 1520 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Text: creative writing | 1514 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Vision | 1322 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Text: English | 1507 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Text: non-English | 1507 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Text: Chinese | 1582 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Text: German | 1503 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Text: Japanese | 1560 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Text: Korean | 1505 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Text: French | 1515 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Text: Spanish | 1510 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Text: Russian | 1518 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Text: Polish | 1537 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Text: multi-turn | 1492 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Text: longer queries | 1523 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Text: writing and language | 1515 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Text: entertainment and media | 1498 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Vision: English | 1316 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Vision: Chinese | 1397 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Vision: reading text | 1329 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Vision: humor | 1326 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Vision: creative writing | 1325 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Document | 1515 | Not measured | Only Claude Fable 5.1 measured |
| Neither model has a result on the other 16 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Claude Fable 5.1 | Claude Fable 5.2 | Leader |
|---|---|---|---|
| Neither model has a result on 5 boards here | |||
What each workload costs
Three fixed token mixes at each model's listed price, so per-token rates become a bill.
Chat turn
1K input + 500 output tokens
Claude Fable 5.1$0.035Fits in one request
Claude Fable 5.2$0.028Fits in one request
Claude Fable 5.2 costs less
Repository review
50K input + 3K output tokens
Claude Fable 5.1$0.650Fits in one request
Claude Fable 5.2$0.520Fits in one request
Claude Fable 5.2 costs less
Agent loop
200K input + 10K output tokens
Claude Fable 5.1$2.50Fits in one request
Claude Fable 5.2$2.00Fits in one request
Claude Fable 5.2 costs less
Listed OpenRouter rates, without cache or batch discounts. A workload that does not fit a model's context window would need splitting.
Specification differences
The leading value in a row is marked; a row with a missing value names no leader. Our two rows are marked in red.
| Specification | Anthropic Claude Fable 5.1 | Anthropic Claude Fable 5.2 |
|---|---|---|
| Maker | Anthropic | Anthropic |
| Weights | No public weights listed | No public weights listed |
| Released | September 1, 2026 | November 9, 2026 |
| Context window | 1M | 1M |
| Input $/Mtok | $10.00 | $8.00 |
| Output $/Mtok | $50.00 | $40.00 |
| Coding index | 82.8 | 87.8 |
| Independent measurements behind it | 5 | 4 |
| Cost per solved task | Not computable | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Claude Fable 5.1 better than Claude Fable 5.2 for coding?
Pick Claude Fable 5.2 for coding: it scores 87.8 on the Vibe Coding Index against 82.8 for Claude Fable 5.1, though on 4 benchmarks against 5. Pick Claude Fable 5.1 for work measured by LiveBench coding or LiveBench browser, where it leads.
Which is cheaper, Claude Fable 5.1 or Claude Fable 5.2?
Claude Fable 5.1 costs $10.00 per million input tokens and $50.00 per million output tokens; Claude Fable 5.2 costs $8.00 and $40.00. Cost per solved task is known for neither of them.
Which has the bigger context window, Claude Fable 5.1 or Claude Fable 5.2?
Neither: both take 1M tokens.
How many benchmarks is the Claude Fable 5.1 vs Claude Fable 5.2 comparison based on?
63 benchmarks have a result for both models as of November 14, 2026. Claude Fable 5.1's coding index rests on 5 independent benchmarks and Claude Fable 5.2's on 4. Where only one model has a result, the page says so instead of naming a winner.