Claude Fable 5.1 vs Claude Haiku 4.5
Claude Fable 5.1 leads Claude Haiku 4.5 on coding, 84.2 to 35.6 on the Vibe Coding Index, and Claude Haiku 4.5 costs 10.0x less per output token ($5.00 vs $50.00 per million). Updated October 22, 2026; 79 benchmarks have a result for both.
vs boards won of 79 shared
Claude Fable 5.1 or Claude Haiku 4.5: which to pick
Pick Claude Fable 5.1 for coding: it scores 84.2 on the Vibe Coding Index against 35.6 for Claude Haiku 4.5.
Pick Claude Haiku 4.5 for output tokens 10.0x cheaper ($5.00 vs $50.00 per million).
Model AClaude Fable 5.1Anthropic84.2/1005 independent benchmarksNo cost per solved taskModel BClaude Haiku 4.5Anthropic35.6/1004 independent benchmarks$0.56 per solved task
- Shared results
- 79
- Claude Fable 5.1 only
- 54
- Claude Haiku 4.5 only
- 19
- 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 5.1
Claude Fable 5.1 scores 84.2 against 35.6.
5 and 4 benchmarks behind the scores
Intelligence
AA Intelligence Index
Claude Fable 5.1
Claude Fable 5.1 leads, 53.4 against 16.9.
Same board, both measured
Agentic work
AA Agentic Index
Claude Fable 5.1
Claude Fable 5.1 leads, 57.9 against 8.0.
Same board, both measured
Reasoning
GPQA Diamond
Claude Fable 5.1
Claude Fable 5.1 leads, 93.4% against 72.2%.
Same board, both measured
Math
AIME
No call
Only Claude Haiku 4.5 has a AIME result, 82.7%.
Directional only
Knowledge
MMLU Pro
Claude Fable 5.1
Claude Fable 5.1 leads, 92.4% against 78.7%.
Same board, both measured
Web design
Design Arena: websites
Claude Fable 5.1
Claude Fable 5.1 leads, 1312 against 1122.
Same board, both measured
Long documents
Listed context window
Claude Fable 5.1
Claude Fable 5.1 takes 1M tokens against 200K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Claude Haiku 4.5
Claude Fable 5.1 $0.035, Claude Haiku 4.5 $0.0035 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
No call
Only Claude Haiku 4.5 has the number, $0.56.
Directional only
At a glance
- Coding index
- Claude Fable 5.1 84.2 from 5 benchmarks, Claude Haiku 4.5 35.6 from 4 benchmarks.
- Widest category
- Agentic work, 46.7 points apart on average over 10 shared benchmarks.
- Widest single gap
- ARC-AGI-2: Claude Fable 5.1 90.0% against Claude Haiku 4.5 4.0%, 86.0 points apart on a 0 to 100 scale.
- Output price
- Claude Fable 5.1 $50.00 against Claude Haiku 4.5 $5.00 per million output tokens, 10.0x apart.
- Context window
- Claude Fable 5.1 takes 1M tokens, Claude Haiku 4.5 200K.
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 Haiku 4.5 | Ties |
|---|---|---|---|---|
| Coding | 13 | 0 | ||
| Intelligence | 2 | 0 | ||
| Agentic work | 10 | 0 | ||
| Reasoning | 9 | 0 | ||
| Math | 3 | 0 | ||
| Knowledge | 10 | 0 | ||
| Web design | 9 | 0 | ||
| General | 23 | 0 | ||
| All shared boards | 79 | 0 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index130
| Benchmark | Claude Fable 5.1 | Claude Haiku 4.5 | Leader |
|---|---|---|---|
| SWE-bench Verified | Not measured | 66.6% | Only Claude Haiku 4.5 measured |
| SWE-bench Multilingual | Not measured | 64.7% | Only Claude Haiku 4.5 measured |
| LiveBench coding | 97.7% | 48.1% | Claude Fable 5.1 |
| LMArena WebDev | 1743 | 1330 | Claude Fable 5.1 |
| AA Coding Index | 81.6 | 43.9 | Claude Fable 5.1 |
| LiveCodeBench (Vals AI) | 90.5% | 41.2% | Claude Fable 5.1 |
| SWE-bench Verified (Vals AI) | Not measured | 66.6% | Only Claude Haiku 4.5 measured |
| Terminal-Bench 4 (Vals AI) | 58.1% | Not measured | Only Claude Fable 5.1 measured |
| Vibe Code Bench (Vals AI) | 90.3% | 11.4% | Claude Fable 5.1 |
| Code migration (Vals AI) | 54.6% | 7.5% | Claude Fable 5.1 |
| ProgramBench (Vals AI) | 7.0% | 0.0% | Claude Fable 5.1 |
| IOI (Vals AI) | 90.8% | Not measured | Only Claude Fable 5.1 measured |
| Terminal-Bench 2.1 (Vals AI) | 85.0% | 43.8% | Claude Fable 5.1 |
| SWE-bench Multimodal (Vals AI) | 61.3% | Not measured | Only Claude Fable 5.1 measured |
| 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% | Not measured | Only Claude Fable 5.1 measured |
| Terminal-Bench | Not measured | 35.5% | Only Claude Haiku 4.5 measured |
| FrontierCode | 50.9% | Not measured | Only Claude Fable 5.1 measured |
| FrontierSWE | 56.3% | Not measured | Only Claude Fable 5.1 measured |
| GSO-Bench | 88.2% | Not measured | Only Claude Fable 5.1 measured |
| WeirdML | 92.9% | 45.4% | Claude Fable 5.1 |
| MirrorCode | 73.3% | Not measured | Only Claude Fable 5.1 measured |
| ALE-Bench | 2143.2 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Text: coding | 1532 | 1454 | Claude Fable 5.1 |
| LMArena Text: software and IT | 1530 | 1439 | Claude Fable 5.1 |
| LMArena WebDev: React | 1792 | 1326 | Claude Fable 5.1 |
| LMArena WebDev: HTML | 1684 | 1318 | Claude Fable 5.1 |
| LMArena WebDev: from an image | 1722 | 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 |
| Neither model has a result on the other 9 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index20
| Benchmark | Claude Fable 5.1 | Claude Haiku 4.5 | Leader |
|---|---|---|---|
| AA Intelligence Index | 53.4 | 16.9 | Claude Fable 5.1 |
| Epoch Capabilities Index | 166.5 | 142.2 | Claude Fable 5.1 |
Agentic workLike-for-likePublic boards, shown as published, kept out of the index100
| Benchmark | Claude Fable 5.1 | Claude Haiku 4.5 | Leader |
|---|---|---|---|
| AA Agentic Index | 57.9 | 8.0 | Claude Fable 5.1 |
| Design Arena: agents building web apps | 1318 | Not measured | Only Claude Fable 5.1 measured |
| Design Arena: agents building full-stack apps | 1326 | Not measured | Only Claude Fable 5.1 measured |
| Design Arena: agents building mobile apps | 1267 | Not measured | Only Claude Fable 5.1 measured |
| Design Arena: agents building Godot games | 1327 | Not measured | Only Claude Fable 5.1 measured |
| Design Arena: PowerPoint slides | 1307 | Not measured | Only Claude Fable 5.1 measured |
| Design Arena: spreadsheets | 1394 | Not measured | Only Claude Fable 5.1 measured |
| LiveBench research | 82.0% | 42.2% | Claude Fable 5.1 |
| LiveBench browser | 100.0% | 40.0% | Claude Fable 5.1 |
| LiveBench long agentic | 80.8% | 11.1% | Claude Fable 5.1 |
| SREBench (Vals AI) | 22.9% | Not measured | Only Claude Fable 5.1 measured |
| Finance Agent (Vals AI) | 58.9% | 31.0% | Claude Fable 5.1 |
| Tax Agent Bench (Vals AI) | 49.2% | 5.9% | Claude Fable 5.1 |
| Legal Research Bench (Vals AI) | 55.3% | 10.6% | Claude Fable 5.1 |
| Excel Modeling Benchmark (Vals AI) | 76.7% | 22.7% | Claude Fable 5.1 |
| Terminal-Bench-Science (Vals AI) | 40.0% | Not measured | Only Claude Fable 5.1 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% | Not measured | Only Claude Fable 5.1 measured |
| Remote Labor Index | 17.9% | Not measured | Only Claude Fable 5.1 measured |
| BALROG | Not measured | 31.2% | Only Claude Haiku 4.5 measured |
| DeepResearch Bench | Not measured | 45.5% | Only Claude Haiku 4.5 measured |
| SpireClimb | 2.0% | Not measured | Only Claude Fable 5.1 measured |
| Vending-Bench 2 | $5,422 | $459 | Claude Fable 5.1 |
| LMArena Search | 1246 | Not measured | Only Claude Fable 5.1 measured |
| Berkeley Function Calling Leaderboard (BFCL) | Not measured | 68.7% | Only Claude Haiku 4.5 measured |
| MCP Atlas | 87.2% | 40.2% | Claude Fable 5.1 |
| Neither model has a result on the other 14 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index90
| Benchmark | Claude Fable 5.1 | Claude Haiku 4.5 | Leader |
|---|---|---|---|
| GPQA Diamond | 93.4% | 72.2% | Claude Fable 5.1 |
| LiveBench reasoning | 91.7% | 61.7% | Claude Fable 5.1 |
| MysteryMechanism (Vals AI) | 47.8% | Not measured | Only Claude Fable 5.1 measured |
| MMMU Pro (Vals AI) | 90.6% | 46.1% | Claude Fable 5.1 |
| GPQA Diamond (Artificial Analysis run) | 93.7% | Not measured | Only Claude Fable 5.1 measured |
| Humanity's Last Exam (Artificial Analysis run) | 59.1% | Not measured | Only Claude Fable 5.1 measured |
| GPQA Diamond (Epoch AI run) | Not measured | 71.2% | Only Claude Haiku 4.5 measured |
| ARC-AGI | 97.5% | 47.7% | Claude Fable 5.1 |
| ARC-AGI-2 | 90.0% | 4.0% | Claude Fable 5.1 |
| Chess puzzles | 48.0% | 8.0% | Claude Fable 5.1 |
| Mystery game puzzles | 58.0% | Not measured | Only Claude Fable 5.1 measured |
| EBR-bench | 57.1% | Not measured | Only Claude Fable 5.1 measured |
| LMArena Text: hard prompts | 1528 | 1421 | Claude Fable 5.1 |
| LMArena Text: expert | 1544 | 1443 | Claude Fable 5.1 |
| LMArena Text: hard prompts in English | 1522 | 1435 | Claude Fable 5.1 |
| LMArena Vision: diagrams | 1343 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Vision: homework | 1345 | Not measured | Only Claude Fable 5.1 measured |
| Humanity's Last Exam (Scale run) | 51.3% | Not measured | Only Claude Fable 5.1 measured |
| Neither model has a result on the other 5 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index30
| Benchmark | Claude Fable 5.1 | Claude Haiku 4.5 | Leader |
|---|---|---|---|
| AIME | Not measured | 82.7% | Only Claude Haiku 4.5 measured |
| MGSM (Vals AI) | Not measured | 92.2% | Only Claude Haiku 4.5 measured |
| OTIS Mock AIME | 100.0% | 66.7% | Claude Fable 5.1 |
| FrontierMath, tiers 1 to 3 | 90.2% | Not measured | Only Claude Fable 5.1 measured |
| FrontierMath, tier 4 | 87.8% | Not measured | Only Claude Fable 5.1 measured |
| ProofBench | 100.0% | Not measured | Only Claude Fable 5.1 measured |
| MATH level 5 | Not measured | 96.4% | Only Claude Haiku 4.5 measured |
| LMArena Text: math | 1531 | 1398 | Claude Fable 5.1 |
| LMArena Text: mathematical work | 1541 | 1430 | Claude Fable 5.1 |
| MathArena | 78.1% | Not measured | Only Claude Fable 5.1 measured |
| Neither model has a result on the other 4 boards here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index100
| Benchmark | Claude Fable 5.1 | Claude Haiku 4.5 | Leader |
|---|---|---|---|
| MMLU Pro | 92.4% | 78.7% | Claude Fable 5.1 |
| LegalBench (Vals AI) | 88.5% | 81.2% | Claude Fable 5.1 |
| CaseLaw (Vals AI) | Not measured | 56.5% | Only Claude Haiku 4.5 measured |
| CorpFin (Vals AI) | Not measured | 60.6% | Only Claude Haiku 4.5 measured |
| TaxEval (Vals AI) | 76.0% | 67.5% | Claude Fable 5.1 |
| MortgageTax (Vals AI) | 70.8% | 62.2% | Claude Fable 5.1 |
| MedQA (Vals AI) | Not measured | 79.6% | Only Claude Haiku 4.5 measured |
| MedCode (Vals AI) | 53.5% | 32.7% | Claude Fable 5.1 |
| SimpleQA Verified | 70.8% | 13.2% | Claude Fable 5.1 |
| LMArena Text: science | 1532 | 1406 | Claude Fable 5.1 |
| LMArena Text: medicine and healthcare | 1531 | 1394 | Claude Fable 5.1 |
| LMArena Text: legal and government | 1514 | 1400 | Claude Fable 5.1 |
| LMArena Text: business and finance | 1493 | 1400 | Claude Fable 5.1 |
| PRBench Finance | 50.8% | Not measured | Only Claude Fable 5.1 measured |
| PRBench Legal | 51.6% | Not measured | Only Claude Fable 5.1 measured |
| Neither model has a result on the other 5 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index90
| Benchmark | Claude Fable 5.1 | Claude Haiku 4.5 | Leader |
|---|---|---|---|
| Design Arena: websites | 1312 | 1122 | Claude Fable 5.1 |
| Design Arena: UI components | 1336 | 1097 | Claude Fable 5.1 |
| Design Arena: game dev | 1381 | 1096 | Claude Fable 5.1 |
| Design Arena: data viz | 1345 | 1124 | Claude Fable 5.1 |
| Design Arena: 3D | 1392 | 1071 | Claude Fable 5.1 |
| Design Arena: all code categories | 1335 | 1114 | Claude Fable 5.1 |
| Design Arena: SVG | 1300 | 1025 | Claude Fable 5.1 |
| Design Arena: ASCII art | 1323 | 1140 | Claude Fable 5.1 |
| LiveBench design | 83.4% | 59.9% | Claude Fable 5.1 |
GeneralLike-for-likePublic boards, shown as published, kept out of the index230
| Benchmark | Claude Fable 5.1 | Claude Haiku 4.5 | Leader |
|---|---|---|---|
| LiveBench data analysis | 80.3% | 59.3% | Claude Fable 5.1 |
| Public Benefits Bench (Vals AI) | 74.9% | 54.3% | Claude Fable 5.1 |
| SAGE (Vals AI) | 48.5% | 31.8% | Claude Fable 5.1 |
| MedScribe (Vals AI) | 91.3% | 85.2% | Claude Fable 5.1 |
| Vals Multimodal Index | Not measured | 42.9% | Only Claude Haiku 4.5 measured |
| Long context reasoning (AA-LCR) | 85.3% | Not measured | Only Claude Fable 5.1 measured |
| DTBench | 97.6% | 73.6% | Claude Fable 5.1 |
| LMCA | 65.5% | 30.9% | Claude Fable 5.1 |
| Furniture assembly | 70.0% | Not measured | Only Claude Fable 5.1 measured |
| ExploitBench | Not measured | 13.7% | Only Claude Haiku 4.5 measured |
| LMArena Text | 1512 | 1397 | Claude Fable 5.1 |
| LMArena Text: instruction following | 1518 | 1414 | Claude Fable 5.1 |
| LMArena Text: creative writing | 1509 | 1371 | Claude Fable 5.1 |
| LMArena Vision | 1319 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Text: English | 1506 | 1414 | Claude Fable 5.1 |
| LMArena Text: non-English | 1508 | 1377 | Claude Fable 5.1 |
| LMArena Text: Chinese | 1584 | 1418 | Claude Fable 5.1 |
| LMArena Text: German | 1499 | 1374 | Claude Fable 5.1 |
| LMArena Text: Japanese | 1562 | 1338 | Claude Fable 5.1 |
| LMArena Text: Korean | 1517 | 1346 | Claude Fable 5.1 |
| LMArena Text: French | 1523 | 1411 | Claude Fable 5.1 |
| LMArena Text: Spanish | 1520 | 1421 | Claude Fable 5.1 |
| LMArena Text: Russian | 1520 | 1381 | Claude Fable 5.1 |
| LMArena Text: Polish | 1525 | 1343 | Claude Fable 5.1 |
| LMArena Text: multi-turn | 1493 | 1409 | Claude Fable 5.1 |
| LMArena Text: longer queries | 1524 | 1427 | Claude Fable 5.1 |
| LMArena Text: writing and language | 1510 | 1386 | Claude Fable 5.1 |
| LMArena Text: entertainment and media | 1497 | 1369 | Claude Fable 5.1 |
| LMArena Vision: English | 1313 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Vision: Chinese | 1391 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Vision: reading text | 1327 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Vision: humor | 1318 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Vision: creative writing | 1330 | Not measured | Only Claude Fable 5.1 measured |
| LMArena Document | Not measured | 1420 | Only Claude Haiku 4.5 measured |
| MultiChallenge | Not measured | 50.5% | Only Claude Haiku 4.5 measured |
| EQ-Bench 4 | Not measured | 1064 | Only Claude Haiku 4.5 measured |
| Neither model has a result on the other 12 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Claude Fable 5.1 | Claude Haiku 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 5.1$0.035Fits in one request
Claude Haiku 4.5$0.0035Fits in one request
Claude Haiku 4.5 costs less
Repository review
50K input + 3K output tokens
Claude Fable 5.1$0.650Fits in one request
Claude Haiku 4.5$0.065Fits in one request
Claude Haiku 4.5 costs less
Agent loop
200K input + 10K output tokens
Claude Fable 5.1$2.50Fits in one request
Claude Haiku 4.5$0.250Exceeds the context window
Claude Haiku 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 5.1 | Anthropic Claude Haiku 4.5 |
|---|---|---|
| Maker | Anthropic | Anthropic |
| Weights | No public weights listed | No public weights listed |
| Released | September 1, 2026 | October 15, 2025 |
| Context window | 1M | 200K |
| Input $/Mtok | $10.00 | $1.00 |
| Output $/Mtok | $50.00 | $5.00 |
| Coding index | 84.2 | 35.6 |
| Independent measurements behind it | 5 | 4 |
| Cost per solved task | Not computable | $0.56 |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Claude Fable 5.1 better than Claude Haiku 4.5 for coding?
Pick Claude Fable 5.1 for coding: it scores 84.2 on the Vibe Coding Index against 35.6 for Claude Haiku 4.5. Pick Claude Haiku 4.5 for output tokens 10.0x cheaper ($5.00 vs $50.00 per million).
Which is cheaper, Claude Fable 5.1 or Claude Haiku 4.5?
Claude Fable 5.1 costs $10.00 per million input tokens and $50.00 per million output tokens; Claude Haiku 4.5 costs $1.00 and $5.00. Cost per solved task is known for Claude Haiku 4.5 only.
Which has the bigger context window, Claude Fable 5.1 or Claude Haiku 4.5?
Claude Fable 5.1, with 1M tokens against 200K.
How many benchmarks is the Claude Fable 5.1 vs Claude Haiku 4.5 comparison based on?
79 benchmarks have a result for both models as of October 22, 2026. Claude Fable 5.1's coding index rests on 5 independent benchmarks and Claude Haiku 4.5's on 4. Where only one model has a result, the page says so instead of naming a winner.