Claude Fable 5 vs Gemma 4 31B
Updated October 21, 2026. 65 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.
Decision reading
Pick Claude Fable 5 for coding: it scores 82.1 on the Vibe Coding Index against 38.3 for Gemma 4 31B.
Pick Gemma 4 31B when output tokens cost 125.0x less, or when what matters is SAGE (Vals AI) or IFBench, where it leads.
- Shared results
- 65
- Claude Fable 5 only
- 61
- Gemma 4 31B only
- 3
- Like-for-like categories
- 8 of 9
Shared results can support a head-to-head reading. Results only one model has describe coverage, not superiority.
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, four public coding benchmarks
Claude Fable 5
Claude Fable 5 scores 82.1 against 38.3.
2 benchmarks behind each score
Intelligence
AA Intelligence Index
Claude Fable 5
Claude Fable 5 leads, 49.6 against 14.7.
Same board, both measured
Agentic work
AA Agentic Index
Claude Fable 5
Claude Fable 5 leads, 50.7 against 4.2.
Same board, both measured
Reasoning
GPQA Diamond
No call
Only Claude Fable 5 has a GPQA Diamond result, 93.2%.
Directional only
Knowledge
MMLU Pro
No call
Only Claude Fable 5 has a MMLU Pro result, 91.5%.
Directional only
Web design
Design Arena: websites
No call
Only Claude Fable 5 has a Design Arena: websites result, 1296.
Directional only
Long documents
Listed context window
Claude Fable 5
Claude Fable 5 takes 1M tokens against 262K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Gemma 4 31B
Claude Fable 5 $0.035, Gemma 4 31B $0.0004 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
No call
Only Claude Fable 5 has the number, $2.16.
Directional only
At a glance
- Coding index
- Claude Fable 5 82.1 from 2 benchmarks, Gemma 4 31B 38.3 from 2 benchmarks.
- Widest category
- Agentic work, 50.0 points apart on average over 5 shared benchmarks.
- Widest single gap
- LiveBench browser: Claude Fable 5 92.0% against Gemma 4 31B 4.0%, 88.0 points apart on a 0 to 100 scale.
- Output price
- Claude Fable 5 $50.00 against Gemma 4 31B $0.40 per million output tokens, 125.0x apart.
- Context window
- Claude Fable 5 takes 1M tokens, Gemma 4 31B 262K.
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 | Bars | Gemma 4 31B | Ties |
|---|---|---|---|---|
| Coding | 11 | 0 | ||
| Intelligence | 2 | 0 | ||
| Agentic work | 5 | 0 | ||
| Reasoning | 9 | 0 | ||
| Math | 3 | 0 | ||
| Knowledge | 6 | 0 | ||
| Web design | 1 | 0 | ||
| General | 26 | 2 | ||
| All shared boards | 63 | 2 |
CodingLike-for-likeFour of these boards feed the Vibe Coding Index110
| Benchmark | Claude Fable 5 | Gemma 4 31B | Leader |
|---|---|---|---|
| LiveBench coding | 98.3% | 49.0% | Claude Fable 5 |
| LMArena WebDev | 1624 | 1367 | Claude Fable 5 |
| AA Coding Index | 76.5 | 43.4 | Claude Fable 5 |
| LiveCodeBench (Vals AI) | 89.8% | Not measured | Only Claude Fable 5 measured |
| SWE-bench Verified (Vals AI) | 95.0% | Not measured | Only Claude Fable 5 measured |
| Terminal-Bench 4 (Vals AI) | 41.4% | Not measured | Only Claude Fable 5 measured |
| Vibe Code Bench (Vals AI) | 90.3% | Not measured | Only Claude Fable 5 measured |
| Code migration (Vals AI) | 55.1% | Not measured | Only Claude Fable 5 measured |
| ProgramBench (Vals AI) | 2.0% | Not measured | Only Claude Fable 5 measured |
| Terminal-Bench 2.1 (Vals AI) | 80.5% | Not measured | Only Claude Fable 5 measured |
| SciCode | 61.0% | 45.5% | Claude Fable 5 |
| Terminal-Bench Hard (Artificial Analysis run) | 62.9% | 36.4% | Claude Fable 5 |
| FrontierCode | 53.5% | Not measured | Only Claude Fable 5 measured |
| FrontierSWE | 47.0% | Not measured | Only Claude Fable 5 measured |
| GSO-Bench | 78.4% | Not measured | Only Claude Fable 5 measured |
| WeirdML | 91.9% | 52.3% | Claude Fable 5 |
| MirrorCode | 63.9% | Not measured | Only Claude Fable 5 measured |
| ALE-Bench | 2041.3 | 925.5 | Claude Fable 5 |
| LMArena Text: coding | 1518 | 1459 | Claude Fable 5 |
| LMArena Text: software and IT | 1513 | 1463 | Claude Fable 5 |
| LMArena WebDev: React | 1631 | 1359 | Claude Fable 5 |
| LMArena WebDev: HTML | 1651 | 1380 | Claude Fable 5 |
| LMArena WebDev: from an image | 1623 | Not measured | Only Claude Fable 5 measured |
| Neither model has a result on the other 15 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index20
| Benchmark | Claude Fable 5 | Gemma 4 31B | Leader |
|---|---|---|---|
| AA Intelligence Index | 49.6 | 14.7 | Claude Fable 5 |
| Epoch Capabilities Index | 163.4 | 143.0 | Claude Fable 5 |
Agentic workLike-for-likePublic boards, shown as published, kept out of the index50
| Benchmark | Claude Fable 5 | Gemma 4 31B | Leader |
|---|---|---|---|
| AA Agentic Index | 50.7 | 4.2 | Claude Fable 5 |
| Design Arena: agents building web apps | 1261 | Not measured | Only Claude Fable 5 measured |
| Design Arena: agents building full-stack apps | 1280 | Not measured | Only Claude Fable 5 measured |
| Design Arena: agents building mobile apps | 1264 | Not measured | Only Claude Fable 5 measured |
| Design Arena: agents building Android apps | 1289 | Not measured | Only Claude Fable 5 measured |
| Design Arena: agents building Godot games | 1292 | Not measured | Only Claude Fable 5 measured |
| Design Arena: agents building games | 1285 | Not measured | Only Claude Fable 5 measured |
| Design Arena: HTML slides | 1277 | Not measured | Only Claude Fable 5 measured |
| Design Arena: PowerPoint slides | 1295 | Not measured | Only Claude Fable 5 measured |
| LiveBench research | 86.9% | 44.4% | Claude Fable 5 |
| LiveBench browser | 92.0% | 4.0% | Claude Fable 5 |
| LiveBench long agentic | 53.2% | 13.3% | Claude Fable 5 |
| Finance Agent (Vals AI) | 56.3% | Not measured | Only Claude Fable 5 measured |
| Tax Agent Bench (Vals AI) | 38.3% | Not measured | Only Claude Fable 5 measured |
| Legal Research Bench (Vals AI) | 49.5% | Not measured | Only Claude Fable 5 measured |
| Excel Modeling Benchmark (Vals AI) | 73.7% | Not measured | Only Claude Fable 5 measured |
| Terminal-Bench-Science (Vals AI) | 15.7% | Not measured | Only Claude Fable 5 measured |
| τ²-Bench Telecom | 98.5% | 65.5% | Claude Fable 5 |
| APEX-Agents | 63.6% | Not measured | Only Claude Fable 5 measured |
| Remote Labor Index | 16.1% | Not measured | Only Claude Fable 5 measured |
| PostTrainBench | 41.8% | Not measured | Only Claude Fable 5 measured |
| Vending-Bench 2 | $5,680 | Not measured | Only Claude Fable 5 measured |
| LMArena Search | 1229 | Not measured | Only Claude Fable 5 measured |
| Neither model has a result on the other 16 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index90
| Benchmark | Claude Fable 5 | Gemma 4 31B | Leader |
|---|---|---|---|
| GPQA Diamond | 93.2% | Not measured | Only Claude Fable 5 measured |
| LiveBench reasoning | 89.7% | 68.3% | Claude Fable 5 |
| MMMU Pro (Vals AI) | 89.3% | Not measured | Only Claude Fable 5 measured |
| GPQA Diamond (Artificial Analysis run) | 92.6% | 85.7% | Claude Fable 5 |
| Humanity's Last Exam (Artificial Analysis run) | 55.5% | 23.6% | Claude Fable 5 |
| GPQA Diamond (Epoch AI run) | 85.9% | 75.8% | Claude Fable 5 |
| ARC-AGI | 98.5% | Not measured | Only Claude Fable 5 measured |
| ARC-AGI-2 | 89.2% | Not measured | Only Claude Fable 5 measured |
| SimpleBench | 81.9% | Not measured | Only Claude Fable 5 measured |
| Chess puzzles | 47.0% | Not measured | Only Claude Fable 5 measured |
| Mystery game puzzles | 52.0% | Not measured | Only Claude Fable 5 measured |
| EBR-bench | 39.5% | Not measured | Only Claude Fable 5 measured |
| LMArena Text: hard prompts | 1507 | 1448 | Claude Fable 5 |
| LMArena Text: expert | 1534 | 1464 | Claude Fable 5 |
| LMArena Text: hard prompts in English | 1509 | 1456 | Claude Fable 5 |
| LMArena Vision: diagrams | 1357 | 1283 | Claude Fable 5 |
| LMArena Vision: homework | 1361 | 1310 | Claude Fable 5 |
| Neither model has a result on the other 4 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index30
| Benchmark | Claude Fable 5 | Gemma 4 31B | Leader |
|---|---|---|---|
| OTIS Mock AIME | 100.0% | 73.3% | Claude Fable 5 |
| FrontierMath, tiers 1 to 3 | 87.0% | Not measured | Only Claude Fable 5 measured |
| FrontierMath, tier 4 | 90.2% | Not measured | Only Claude Fable 5 measured |
| ProofBench | 95.0% | Not measured | Only Claude Fable 5 measured |
| LMArena Text: math | 1516 | 1463 | Claude Fable 5 |
| LMArena Text: mathematical work | 1515 | 1465 | Claude Fable 5 |
| Neither model has a result on the other 7 boards here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index60
| Benchmark | Claude Fable 5 | Gemma 4 31B | Leader |
|---|---|---|---|
| MMLU Pro | 91.5% | Not measured | Only Claude Fable 5 measured |
| LegalBench (Vals AI) | 88.6% | Not measured | Only Claude Fable 5 measured |
| CaseLaw (Vals AI) | Not measured | 52.6% | Only Gemma 4 31B measured |
| CorpFin (Vals AI) | 71.8% | Not measured | Only Claude Fable 5 measured |
| TaxEval (Vals AI) | 76.9% | Not measured | Only Claude Fable 5 measured |
| MortgageTax (Vals AI) | 68.9% | 61.4% | Claude Fable 5 |
| MedCode (Vals AI) | 56.1% | Not measured | Only Claude Fable 5 measured |
| SimpleQA Verified | 70.7% | 10.4% | Claude Fable 5 |
| LMArena Text: science | 1506 | 1457 | Claude Fable 5 |
| LMArena Text: medicine and healthcare | 1480 | 1451 | Claude Fable 5 |
| LMArena Text: legal and government | 1498 | 1438 | Claude Fable 5 |
| LMArena Text: business and finance | 1480 | 1430 | Claude Fable 5 |
| Neither model has a result on the other 5 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index10
| Benchmark | Claude Fable 5 | Gemma 4 31B | Leader |
|---|---|---|---|
| Design Arena: websites | 1296 | Not measured | Only Claude Fable 5 measured |
| Design Arena: UI components | 1318 | Not measured | Only Claude Fable 5 measured |
| Design Arena: game dev | 1336 | Not measured | Only Claude Fable 5 measured |
| Design Arena: data viz | 1304 | Not measured | Only Claude Fable 5 measured |
| Design Arena: 3D | 1319 | Not measured | Only Claude Fable 5 measured |
| Design Arena: all code categories | 1310 | Not measured | Only Claude Fable 5 measured |
| Design Arena: SVG | 1302 | Not measured | Only Claude Fable 5 measured |
| Design Arena: ASCII art | 1328 | Not measured | Only Claude Fable 5 measured |
| LiveBench design | 84.7% | 58.4% | Claude Fable 5 |
GeneralLike-for-likePublic boards, shown as published, kept out of the index262
| Benchmark | Claude Fable 5 | Gemma 4 31B | Leader |
|---|---|---|---|
| LiveBench data analysis | 80.5% | 53.3% | Claude Fable 5 |
| Public Benefits Bench (Vals AI) | 70.4% | Not measured | Only Claude Fable 5 measured |
| SAGE (Vals AI) | 51.9% | 55.0% | Gemma 4 31B |
| MedScribe (Vals AI) | 88.5% | Not measured | Only Claude Fable 5 measured |
| Vals Multimodal Index | 74.2% | Not measured | Only Claude Fable 5 measured |
| IFBench | 63.5% | 75.6% | Gemma 4 31B |
| Long context reasoning (AA-LCR) | 82.3% | 69.7% | Claude Fable 5 |
| DTBench | 98.4% | 82.7% | Claude Fable 5 |
| LMCA | 61.2% | 39.3% | Claude Fable 5 |
| Surface Evolver Bench | 95.0% | 30.6% | Claude Fable 5 |
| Furniture assembly | 35.8% | Not measured | Only Claude Fable 5 measured |
| LMArena Text | 1491 | 1443 | Claude Fable 5 |
| LMArena Text: instruction following | 1502 | 1433 | Claude Fable 5 |
| LMArena Text: creative writing | 1494 | 1417 | Claude Fable 5 |
| LMArena Vision | 1325 | 1276 | Claude Fable 5 |
| LMArena Text: English | 1498 | 1451 | Claude Fable 5 |
| LMArena Text: non-English | 1482 | 1430 | Claude Fable 5 |
| LMArena Text: Chinese | 1543 | 1475 | Claude Fable 5 |
| LMArena Text: German | 1486 | Not measured | Only Claude Fable 5 measured |
| LMArena Text: Japanese | 1504 | Not measured | Only Claude Fable 5 measured |
| LMArena Text: Korean | 1487 | Not measured | Only Claude Fable 5 measured |
| LMArena Text: French | 1505 | 1436 | Claude Fable 5 |
| LMArena Text: Spanish | 1498 | 1442 | Claude Fable 5 |
| LMArena Text: Russian | 1503 | 1460 | Claude Fable 5 |
| LMArena Text: Polish | 1494 | 1433 | Claude Fable 5 |
| LMArena Text: multi-turn | 1504 | 1452 | Claude Fable 5 |
| LMArena Text: longer queries | 1510 | 1446 | Claude Fable 5 |
| LMArena Text: writing and language | 1501 | 1432 | Claude Fable 5 |
| LMArena Text: entertainment and media | 1482 | 1405 | Claude Fable 5 |
| LMArena Vision: English | 1323 | 1271 | Claude Fable 5 |
| LMArena Vision: Chinese | 1373 | 1326 | Claude Fable 5 |
| LMArena Vision: reading text | 1337 | 1282 | Claude Fable 5 |
| LMArena Vision: humor | 1341 | 1280 | Claude Fable 5 |
| LMArena Vision: captioning | Not measured | 1218 | Only Gemma 4 31B measured |
| LMArena Vision: recognizing things | Not measured | 1226 | Only Gemma 4 31B measured |
| LMArena Vision: creative writing | 1338 | 1285 | Claude Fable 5 |
| LMArena Document | 1496 | 1425 | Claude Fable 5 |
| Neither model has a result on the other 9 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Claude Fable 5 | Gemma 4 31B | 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
Gemma 4 31B costs less
Repository review
50K input + 3K output tokens
Gemma 4 31B costs less
Agent loop
200K input + 10K output tokens
Gemma 4 31B 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 | Google Gemma 4 31B |
|---|---|---|
| Maker | Anthropic | |
| Weights | No public weights listed | Open weights |
| Released | June 9, 2026 | April 2, 2026 |
| Context window | 1M | 262K |
| Input $/Mtok | $10.00 | $0.20 |
| Output $/Mtok | $50.00 | $0.40 |
| Coding index | 82.1 | 38.3 |
| Independent measurements behind it | 2 | 2 |
| Cost per solved task | $2.16 | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Claude Fable 5 better than Gemma 4 31B for coding?
Pick Claude Fable 5 for coding: it scores 82.1 on the Vibe Coding Index against 38.3 for Gemma 4 31B. Pick Gemma 4 31B when output tokens cost 125.0x less, or when what matters is SAGE (Vals AI) or IFBench, where it leads.
Which is cheaper, Claude Fable 5 or Gemma 4 31B?
Claude Fable 5 costs $10.00 per million input tokens and $50.00 per million output tokens; Gemma 4 31B costs $0.20 and $0.40. Cost per solved task is known for Claude Fable 5 only.
Which has the bigger context window, Claude Fable 5 or Gemma 4 31B?
Claude Fable 5, with 1M tokens against 262K.
How many benchmarks is the Claude Fable 5 vs Gemma 4 31B comparison based on?
65 benchmarks have a result for both models as of October 21, 2026. Claude Fable 5's coding index rests on 2 independent benchmarks and Gemma 4 31B's on 2. Where only one model has a result, the page says so instead of naming a winner.