Claude Fable 5.2 vs Claude Sonnet 4.5
Claude Fable 5.2 leads Claude Sonnet 4.5 on coding, 87.8 to 39.5 on the Vibe Coding Index, and Claude Sonnet 4.5 costs 2.7x less per output token ($15.00 vs $40.00 per million). Updated November 14, 2026; 30 benchmarks have a result for both.
vs boards won of 30 shared
Claude Fable 5.2 or Claude Sonnet 4.5: which to pick
Pick Claude Fable 5.2 for coding: it scores 87.8 on the Vibe Coding Index against 39.5 for Claude Sonnet 4.5.
Pick Claude Sonnet 4.5 for output tokens 2.7x cheaper ($15.00 vs $40.00 per million).
Model AClaude Fable 5.2Anthropic87.8/1004 independent benchmarksNo cost per solved taskModel BClaude Sonnet 4.5Anthropic39.5/1003 independent benchmarks$1.16 per solved task
- Shared results
- 30
- Claude Fable 5.2 only
- 38
- Claude Sonnet 4.5 only
- 70
- 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 39.5.
4 and 3 benchmarks behind the scores
Intelligence
AA Intelligence Index
No call
Only Claude Fable 5.2 has a AA Intelligence Index result, 64.6.
Directional only
Agentic work
AA Agentic Index
No call
Only Claude Sonnet 4.5 has a AA Agentic Index result, 15.8.
Directional only
Reasoning
GPQA Diamond
No call
Only Claude Sonnet 4.5 has a GPQA Diamond result, 81.6%.
Directional only
Math
AIME
No call
Only Claude Sonnet 4.5 has a AIME result, 88.2%.
Directional only
Knowledge
MMLU Pro
No call
Only Claude Sonnet 4.5 has a MMLU Pro result, 87.4%.
Directional only
Web design
Design Arena: websites
Claude Fable 5.2
Claude Fable 5.2 leads, 1351 against 1181.
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 Sonnet 4.5
Claude Fable 5.2 $0.028, Claude Sonnet 4.5 $0.011 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
No call
Only Claude Sonnet 4.5 has the number, $1.16.
Directional only
At a glance
- Coding index
- Claude Fable 5.2 87.8 from 4 benchmarks, Claude Sonnet 4.5 39.5 from 3 benchmarks.
- Widest category
- Math, 68.3 points apart on average over 5 shared benchmarks.
- Widest single gap
- FrontierMath, tier 4: Claude Fable 5.2 100.0% against Claude Sonnet 4.5 2.4%, 97.6 points apart on a 0 to 100 scale.
- Output price
- Claude Fable 5.2 $40.00 against Claude Sonnet 4.5 $15.00 per million output tokens, 2.7x 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 5.2 | Bars | Claude Sonnet 4.5 | Ties |
|---|---|---|---|---|
| Coding | 4 | 0 | ||
| Intelligence | 1 | 0 | ||
| Agentic work | 3 | 0 | ||
| Reasoning | 7 | 0 | ||
| Math | 5 | 0 | ||
| Knowledge | 3 | 0 | ||
| Web design | 5 | 0 | ||
| General | 2 | 0 | ||
| All shared boards | 30 | 0 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index40
| Benchmark | Claude Fable 5.2 | Claude Sonnet 4.5 | Leader |
|---|---|---|---|
| SWE-bench Verified | Not measured | 74.8% | Only Claude Sonnet 4.5 measured |
| SWE-bench Multilingual | Not measured | 67.0% | Only Claude Sonnet 4.5 measured |
| LiveBench coding | 79.2% | Not measured | Only Claude Fable 5.2 measured |
| LMArena WebDev | 1838 | 1393 | Claude Fable 5.2 |
| AA Coding Index | Not measured | 52.1 | Only Claude Sonnet 4.5 measured |
| LiveCodeBench (Vals AI) | Not measured | 73.0% | Only Claude Sonnet 4.5 measured |
| SWE-bench Verified (Vals AI) | Not measured | 70.0% | Only Claude Sonnet 4.5 measured |
| Terminal-Bench 4 (Vals AI) | 65.2% | Not measured | Only Claude Fable 5.2 measured |
| Vibe Code Bench (Vals AI) | 93.8% | 22.6% | Claude Fable 5.2 |
| ProgramBench (Vals AI) | 19.0% | Not measured | Only Claude Fable 5.2 measured |
| SWE-bench Multimodal (Vals AI) | 62.3% | Not measured | Only Claude Fable 5.2 measured |
| SciCode | 67.7% | Not measured | Only Claude Fable 5.2 measured |
| Terminal-Bench 4.0 (Artificial Analysis run) | 61.6% | Not measured | Only Claude Fable 5.2 measured |
| FrontierCode 2.0 | 49.1% | Not measured | Only Claude Fable 5.2 measured |
| Terminal-Bench | Not measured | 46.5% | Only Claude Sonnet 4.5 measured |
| FrontierSWE | 69.9% | Not measured | Only Claude Fable 5.2 measured |
| GSO-Bench | Not measured | 14.7% | Only Claude Sonnet 4.5 measured |
| WeirdML | Not measured | 47.7% | Only Claude Sonnet 4.5 measured |
| Cybench | Not measured | 60.0% | Only Claude Sonnet 4.5 measured |
| ALE-Bench | 2509.8 | Not measured | Only Claude Fable 5.2 measured |
| LMArena Text: coding | Not measured | 1488 | Only Claude Sonnet 4.5 measured |
| LMArena Text: software and IT | Not measured | 1473 | Only Claude Sonnet 4.5 measured |
| LMArena WebDev: React | 1915 | 1386 | Claude Fable 5.2 |
| LMArena WebDev: HTML | 1738 | 1398 | Claude Fable 5.2 |
| GameBench 2 | 99.1 | Not measured | Only Claude Fable 5.2 measured |
| Terminal-Bench 2.0 | Not measured | 46.5% | Only Claude Sonnet 4.5 measured |
| CursorBench 4.0 | 60.0% | Not measured | Only Claude Fable 5.2 measured |
| Neither model has a result on the other 25 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index10
| Benchmark | Claude Fable 5.2 | Claude Sonnet 4.5 | Leader |
|---|---|---|---|
| AA Intelligence Index | 64.6 | Not measured | Only Claude Fable 5.2 measured |
| Epoch Capabilities Index | 173.4 | 147.6 | Claude Fable 5.2 |
Agentic workLike-for-likePublic boards, shown as published, kept out of the index30
| Benchmark | Claude Fable 5.2 | Claude Sonnet 4.5 | Leader |
|---|---|---|---|
| AA Agentic Index | Not measured | 15.8 | Only Claude Sonnet 4.5 measured |
| Design Arena: agents building web apps | Not measured | 1036 | Only Claude Sonnet 4.5 measured |
| Design Arena: agents building full-stack apps | 1402 | 1024 | Claude Fable 5.2 |
| Design Arena: agents building mobile apps | 1325 | 1130 | Claude Fable 5.2 |
| Design Arena: spreadsheets | 1434 | Not measured | Only Claude Fable 5.2 measured |
| LiveBench research | 94.5% | Not measured | Only Claude Fable 5.2 measured |
| LiveBench browser | 86.9% | Not measured | Only Claude Fable 5.2 measured |
| LiveBench long agentic | 82.9% | Not measured | Only Claude Fable 5.2 measured |
| Tax Agent Bench (Vals AI) | 32.1% | Not measured | Only Claude Fable 5.2 measured |
| Legal Research Bench (Vals AI) | 46.1% | Not measured | Only Claude Fable 5.2 measured |
| Harvey's Legal Agent Benchmark (Vals AI) | 5.0% | Not measured | Only Claude Fable 5.2 measured |
| BioMysteryBench (Vals AI) | 83.7% | Not measured | Only Claude Fable 5.2 measured |
| Terminal-Bench-Science (Vals AI) | 55.7% | Not measured | Only Claude Fable 5.2 measured |
| Vals Science Index | 63.7% | Not measured | Only Claude Fable 5.2 measured |
| APEX-Agents | 80.1% | Not measured | Only Claude Fable 5.2 measured |
| METR time horizons | Not measured | 67.4% | Only Claude Sonnet 4.5 measured |
| Remote Labor Index | 41.3% | 2.1% | Claude Fable 5.2 |
| GDPval | Not measured | 42.5% | Only Claude Sonnet 4.5 measured |
| DeepResearch Bench | Not measured | 52.6% | Only Claude Sonnet 4.5 measured |
| OSWorld | Not measured | 62.9% | Only Claude Sonnet 4.5 measured |
| SpireClimb | 15.5% | Not measured | Only Claude Fable 5.2 measured |
| Vending-Bench 2 | Not measured | $3,839 | Only Claude Sonnet 4.5 measured |
| LMArena Search | Not measured | 1159 | Only Claude Sonnet 4.5 measured |
| Berkeley Function Calling Leaderboard (BFCL) | Not measured | 73.2% | Only Claude Sonnet 4.5 measured |
| MCP Atlas | Not measured | 59.5% | Only Claude Sonnet 4.5 measured |
| Neither model has a result on the other 19 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index70
| Benchmark | Claude Fable 5.2 | Claude Sonnet 4.5 | Leader |
|---|---|---|---|
| GPQA Diamond | Not measured | 81.6% | Only Claude Sonnet 4.5 measured |
| LiveBench reasoning | 88.8% | Not measured | Only Claude Fable 5.2 measured |
| MysteryMechanism (Vals AI) | 51.8% | Not measured | Only Claude Fable 5.2 measured |
| MMMU Pro (Vals AI) | Not measured | 79.3% | Only Claude Sonnet 4.5 measured |
| Humanity's Last Exam (Artificial Analysis run) | 74.3% | Not measured | Only Claude Fable 5.2 measured |
| HLE-Diamond (Artificial Analysis run) | 80.2% | Not measured | Only Claude Fable 5.2 measured |
| CritPt v2, hard subset (Artificial Analysis run) | 76.5% | Not measured | Only Claude Fable 5.2 measured |
| GPQA Diamond (Epoch AI run) | 93.9% | 82.3% | Claude Fable 5.2 |
| ARC-AGI | 98.5% | 63.7% | Claude Fable 5.2 |
| ARC-AGI-2 | 93.8% | 13.6% | Claude Fable 5.2 |
| SimpleBench | 94.9% | 54.3% | Claude Fable 5.2 |
| Chess puzzles | 79.0% | 10.0% | Claude Fable 5.2 |
| Mystery game puzzles | 90.0% | 17.0% | Claude Fable 5.2 |
| EBR-bench | 90.5% | 2.4% | Claude Fable 5.2 |
| VPCT | Not measured | 39.8% | Only Claude Sonnet 4.5 measured |
| LMArena Text: hard prompts | Not measured | 1462 | Only Claude Sonnet 4.5 measured |
| LMArena Text: expert | Not measured | 1483 | Only Claude Sonnet 4.5 measured |
| LMArena Text: hard prompts in English | Not measured | 1471 | Only Claude Sonnet 4.5 measured |
| Kagi LLM Benchmark | Not measured | 57.9% | Only Claude Sonnet 4.5 measured |
| Humanity's Last Exam (Scale run) | 72.4% | Not measured | Only Claude Fable 5.2 measured |
| GoBench | 2566 | Not measured | Only Claude Fable 5.2 measured |
| Neither model has a result on the other 5 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index50
| Benchmark | Claude Fable 5.2 | Claude Sonnet 4.5 | Leader |
|---|---|---|---|
| AIME | Not measured | 88.2% | Only Claude Sonnet 4.5 measured |
| MGSM (Vals AI) | Not measured | 94.3% | Only Claude Sonnet 4.5 measured |
| OTIS Mock AIME | 99.7% | 77.8% | Claude Fable 5.2 |
| FrontierMath, tiers 1 to 3 | 95.1% | 23.9% | Claude Fable 5.2 |
| FrontierMath, tier 4 | 100.0% | 2.4% | Claude Fable 5.2 |
| ProofBench | 100.0% | 19.0% | Claude Fable 5.2 |
| MATH level 5 | Not measured | 97.7% | Only Claude Sonnet 4.5 measured |
| LMArena Text: math | Not measured | 1449 | Only Claude Sonnet 4.5 measured |
| LMArena Text: mathematical work | Not measured | 1463 | Only Claude Sonnet 4.5 measured |
| MathArena | 82.8% | 13.2% | Claude Fable 5.2 |
| Neither model has a result on the other 4 boards here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index30
| Benchmark | Claude Fable 5.2 | Claude Sonnet 4.5 | Leader |
|---|---|---|---|
| MMLU Pro | Not measured | 87.4% | Only Claude Sonnet 4.5 measured |
| LegalBench (Vals AI) | Not measured | 84.1% | Only Claude Sonnet 4.5 measured |
| CaseLaw (Vals AI) | Not measured | 62.2% | Only Claude Sonnet 4.5 measured |
| CorpFin (Vals AI) | Not measured | 62.0% | Only Claude Sonnet 4.5 measured |
| TaxEval (Vals AI) | Not measured | 73.3% | Only Claude Sonnet 4.5 measured |
| MortgageTax (Vals AI) | Not measured | 64.0% | Only Claude Sonnet 4.5 measured |
| MedQA (Vals AI) | Not measured | 94.7% | Only Claude Sonnet 4.5 measured |
| MedCode (Vals AI) | Not measured | 44.1% | Only Claude Sonnet 4.5 measured |
| AA-Omniscience | 66.8 | Not measured | Only Claude Fable 5.2 measured |
| SimpleQA Verified | 94.0% | 30.7% | Claude Fable 5.2 |
| GeoBench | Not measured | 60.0% | Only Claude Sonnet 4.5 measured |
| LMArena Text: science | Not measured | 1447 | Only Claude Sonnet 4.5 measured |
| LMArena Text: medicine and healthcare | Not measured | 1443 | Only Claude Sonnet 4.5 measured |
| LMArena Text: legal and government | Not measured | 1450 | Only Claude Sonnet 4.5 measured |
| LMArena Text: business and finance | Not measured | 1440 | Only Claude Sonnet 4.5 measured |
| PRBench Finance | 47.1% | 43.8% | Claude Fable 5.2 |
| PRBench Legal | 49.0% | 40.8% | Claude Fable 5.2 |
| Neither model has a result on the other 4 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index50
| Benchmark | Claude Fable 5.2 | Claude Sonnet 4.5 | Leader |
|---|---|---|---|
| Design Arena: websites | 1351 | 1181 | Claude Fable 5.2 |
| Design Arena: UI components | 1371 | 1162 | Claude Fable 5.2 |
| Design Arena: game dev | 1396 | 1155 | Claude Fable 5.2 |
| Design Arena: data viz | Not measured | 1164 | Only Claude Sonnet 4.5 measured |
| Design Arena: 3D | 1517 | 1137 | Claude Fable 5.2 |
| Design Arena: all code categories | 1373 | 1172 | Claude Fable 5.2 |
| Design Arena: SVG | Not measured | 1104 | Only Claude Sonnet 4.5 measured |
| Design Arena: ASCII art | Not measured | 1200 | Only Claude Sonnet 4.5 measured |
| LiveBench design | 85.1% | Not measured | Only Claude Fable 5.2 measured |
GeneralLike-for-likePublic boards, shown as published, kept out of the index20
| Benchmark | Claude Fable 5.2 | Claude Sonnet 4.5 | Leader |
|---|---|---|---|
| Vals Index | 71.3% | Not measured | Only Claude Fable 5.2 measured |
| LiveBench data analysis | 81.5% | Not measured | Only Claude Fable 5.2 measured |
| MedScribe (Vals AI) | Not measured | 84.5% | Only Claude Sonnet 4.5 measured |
| Long context reasoning (AA-LCR) | 83.3% | Not measured | Only Claude Fable 5.2 measured |
| GDPval-AA | 1831 | Not measured | Only Claude Fable 5.2 measured |
| DTBench | 99.2% | 83.2% | Claude Fable 5.2 |
| LMCA | 70.6% | 38.8% | Claude Fable 5.2 |
| Furniture assembly | 90.0% | Not measured | Only Claude Fable 5.2 measured |
| LMArena Text | Not measured | 1439 | Only Claude Sonnet 4.5 measured |
| LMArena Text: instruction following | Not measured | 1459 | Only Claude Sonnet 4.5 measured |
| LMArena Text: creative writing | Not measured | 1442 | Only Claude Sonnet 4.5 measured |
| LMArena Text: English | Not measured | 1450 | Only Claude Sonnet 4.5 measured |
| LMArena Text: non-English | Not measured | 1425 | Only Claude Sonnet 4.5 measured |
| LMArena Text: Chinese | Not measured | 1461 | Only Claude Sonnet 4.5 measured |
| LMArena Text: German | Not measured | 1427 | Only Claude Sonnet 4.5 measured |
| LMArena Text: Japanese | Not measured | 1389 | Only Claude Sonnet 4.5 measured |
| LMArena Text: Korean | Not measured | 1400 | Only Claude Sonnet 4.5 measured |
| LMArena Text: French | Not measured | 1459 | Only Claude Sonnet 4.5 measured |
| LMArena Text: Spanish | Not measured | 1457 | Only Claude Sonnet 4.5 measured |
| LMArena Text: Russian | Not measured | 1437 | Only Claude Sonnet 4.5 measured |
| LMArena Text: Polish | Not measured | 1423 | Only Claude Sonnet 4.5 measured |
| LMArena Text: multi-turn | Not measured | 1465 | Only Claude Sonnet 4.5 measured |
| LMArena Text: longer queries | Not measured | 1476 | Only Claude Sonnet 4.5 measured |
| LMArena Text: writing and language | Not measured | 1442 | Only Claude Sonnet 4.5 measured |
| LMArena Text: entertainment and media | Not measured | 1429 | Only Claude Sonnet 4.5 measured |
| LMArena Document | Not measured | 1449 | Only Claude Sonnet 4.5 measured |
| MultiChallenge | Not measured | 55.3% | Only Claude Sonnet 4.5 measured |
| Neither model has a result on the other 22 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Claude Fable 5.2 | Claude Sonnet 4.5 | 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 5.2$0.028Fits in one request
Claude Sonnet 4.5$0.011Fits in one request
Claude Sonnet 4.5 costs less
Repository review
50K input + 3K output tokens
Claude Fable 5.2$0.520Fits in one request
Claude Sonnet 4.5$0.195Fits in one request
Claude Sonnet 4.5 costs less
Agent loop
200K input + 10K output tokens
Claude Fable 5.2$2.00Fits in one request
Claude Sonnet 4.5$0.750Fits in one request
Claude Sonnet 4.5 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 5.2 | Anthropic Claude Sonnet 4.5 |
|---|---|---|
| Maker | Anthropic | Anthropic |
| Weights | No public weights listed | No public weights listed |
| Released | November 9, 2026 | September 29, 2025 |
| Context window | 1M | 1M |
| Input $/Mtok | $8.00 | $3.00 |
| Output $/Mtok | $40.00 | $15.00 |
| Coding index | 87.8 | 39.5 |
| Independent measurements behind it | 4 | 3 |
| Cost per solved task | Not computable | $1.16 |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Claude Fable 5.2 better than Claude Sonnet 4.5 for coding?
Pick Claude Fable 5.2 for coding: it scores 87.8 on the Vibe Coding Index against 39.5 for Claude Sonnet 4.5. Pick Claude Sonnet 4.5 for output tokens 2.7x cheaper ($15.00 vs $40.00 per million).
Which is cheaper, Claude Fable 5.2 or Claude Sonnet 4.5?
Claude Fable 5.2 costs $8.00 per million input tokens and $40.00 per million output tokens; Claude Sonnet 4.5 costs $3.00 and $15.00. Cost per solved task is known for Claude Sonnet 4.5 only.
Which has the bigger context window, Claude Fable 5.2 or Claude Sonnet 4.5?
Neither: both take 1M tokens.
How many benchmarks is the Claude Fable 5.2 vs Claude Sonnet 4.5 comparison based on?
30 benchmarks have a result for both models as of November 14, 2026. Claude Fable 5.2's coding index rests on 4 independent benchmarks and Claude Sonnet 4.5's on 3. Where only one model has a result, the page says so instead of naming a winner.