Model comparison
Claude Fable 5 vs Grok 4.3
Claude Fable 5 is the stronger model overall, scoring 66.8 to 43.8 on the Noometry Index. Grok 4.3 costs 13× less per token, which makes it the better buy when Claude Fable 5's lead doesn't matter for your workload.
Last verified . 39 shared benchmarks.
Summary
- They share 39 benchmarks with published results for both. Claude Fable 5 scores higher in 10 categories and Grok 4.3 in 0 categories; 10 gaps are clear of the uncertainty.
- The widest gap is in math, where Claude Fable 5 leads 88.5 to 46.0.
- The biggest single-benchmark swing is ProofBench: 95% for Claude Fable 5 and 11% for Grok 4.3.
- Grok 4.3 is cheaper at $1.25 / $2.50 per million input/output tokens, against $10 / $50 for Claude Fable 5.
Side by side
| Claude Fable 5 | Grok 4.3 | |
|---|---|---|
| Provider | Anthropic | xAI |
| Noometry Index | 66.8 | 43.8 |
| Released | 2026-06-07 | 2026-04-17 |
| Weights | Proprietary | Proprietary |
| Context window | 1M | 1M |
| Max output | 128K | 30K |
| Input $ / M tokens | $10 | $1.25 |
| Output $ / M tokens | $50 | $2.50 |
| Results tracked | 62 | 40 |
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Category by category
Coding Claude Fable 5 leads
Claude Fable 5: 70.6 (#4), Grok 4.3: 41.6 (#121)
| Benchmark | Claude Fable 5 | Grok 4.3 |
|---|---|---|
| LMArena WebDev | 1625 | 1357 |
| SciCode | 61% | 47.3% |
| WeirdML | 91.9% | 49.9% |
| LMArena Coding | 1519 | 1415 |
| ALE-Bench | 2,041 | 944.17 |
| DeepSWE | 69.9% | — |
| FrontierCode | 53.5% | — |
| FrontierSWE | 47% | — |
| GSO | 78.4% | — |
| MirrorCode | 63.9% | — |
Agentic & Tool Use Claude Fable 5 leads
Claude Fable 5: 54.0 (#2), Grok 4.3: 27.7 (#99)
| Benchmark | Claude Fable 5 | Grok 4.3 |
|---|---|---|
| GDP.pdf | 30% | 8% |
| LMArena Search | 1230 | 1165 |
| Vending-Bench 2 | 5,680 | 35.26 |
| APEX-Agents | 63.6% | — |
| Remote Labor Index | 16.1% | — |
| τ²-bench Banking | 39.7% | — |
| PostTrainBench | 41.8% | — |
| GBAEval | 74.5% | — |
Reasoning Claude Fable 5 leads
Claude Fable 5: 76.8 (#6), Grok 4.3: 35.9 (#68)
| Benchmark | Claude Fable 5 | Grok 4.3 |
|---|---|---|
| NYT Connections (extended) | 92.7% | 55.2% |
| CritPt | 28.6% | 8% |
| Chess Puzzles | 41% | 25% |
| LMArena Hard Prompts | 1508 | 1396 |
| DTBench | 98.4% | 90.7% |
| LMCA | 61.1% | 38.3% |
| Epoch Capabilities Index | 162.06 | 149.16 |
| ARC-AGI-2 | 89.2% | — |
| SimpleBench | 81.9% | — |
| Kagi LLM Benchmark | 91.4% | — |
| ARC-AGI-1 | 98.5% | — |
| EnigmaEval | 39.3% | — |
| EBR-Bench | 39.5% | — |
| Mystery Game Puzzles | 52% | — |
| Surface Evolver Bench | 95% | — |
| Bench to the Future 3 | 0.13 | — |
| ForecastBench | — | 60.3 |
Math Claude Fable 5 leads
Claude Fable 5: 88.5 (#5), Grok 4.3: 46.0 (#74)
| Benchmark | Claude Fable 5 | Grok 4.3 |
|---|---|---|
| FrontierMath (Tiers 1-3) | 87% | 42.8% |
| FrontierMath Tier 4 | 90.2% | 14.6% |
| OTIS Mock AIME 2024-2025 | 100% | 93.3% |
| ProofBench | 95% | 11% |
| LMArena Math | 1519 | 1388 |
| FrontierMath Erdős | 0% | — |
Knowledge Claude Fable 5 leads
Claude Fable 5: 62.2 (#25), Grok 4.3: 52.5 (#62)
| Benchmark | Claude Fable 5 | Grok 4.3 |
|---|---|---|
| GPQA Diamond | 85.9% | 88.8% |
| SimpleQA Verified | 70.7% | 33.2% |
| LMArena Expert | 1534 | 1385 |
Multimodal Claude Fable 5 leads
Claude Fable 5: 45.3 (#17), Grok 4.3: 31.6 (#104)
| Benchmark | Claude Fable 5 | Grok 4.3 |
|---|---|---|
| LMArena Vision | 1324 | 1229 |
| Blueprint-Bench 2 | 38.6% | 0% |
| Furniture Assembly | 35.8% | — |
| LMArena Document | 1496 | — |
Multilingual Claude Fable 5 leads
Claude Fable 5: 57.3 (#9), Grok 4.3: 50.5 (#120)
| Benchmark | Claude Fable 5 | Grok 4.3 |
|---|---|---|
| LMArena Non-English | 1481 | 1385 |
| LMArena Chinese | 1543 | 1422 |
| LMArena French | 1505 | 1412 |
| LMArena German | 1486 | 1395 |
| LMArena Japanese | 1506 | 1379 |
| LMArena Korean | 1488 | 1356 |
| LMArena Russian | 1504 | 1399 |
| LMArena Spanish | 1498 | 1398 |
Instruction Following Claude Fable 5 leads
Claude Fable 5: 78.6 (#8), Grok 4.3: 72.1 (#140)
| Benchmark | Claude Fable 5 | Grok 4.3 |
|---|---|---|
| LMArena Instruction Following | 1502 | 1366 |
Long Context Claude Fable 5 leads
Claude Fable 5: 46.3 (#23), Grok 4.3: 42.5 (#123)
| Benchmark | Claude Fable 5 | Grok 4.3 |
|---|---|---|
| LMArena Longer Query | 1509 | 1393 |
Writing & Preference Claude Fable 5 leads
Claude Fable 5: 75.9 (#5), Grok 4.3: 58.5 (#118)
| Benchmark | Claude Fable 5 | Grok 4.3 |
|---|---|---|
| LMArena Text | 1491 | 1397 |
| LMArena Creative Writing | 1494 | 1380 |
| EQ-Bench 4 | 1340 | 1075 |
| LMArena Multi-Turn | 1504 | 1406 |
| EQ-Bench Creative Writing | 1943 | — |
Frequently asked questions
Is Claude Fable 5 better than Grok 4.3?
Claude Fable 5 is the stronger model overall, scoring 66.8 to 43.8 on the Noometry Index. Grok 4.3 costs 13× less per token, which makes it the better buy when Claude Fable 5's lead doesn't matter for your workload.
Which is cheaper, Claude Fable 5 or Grok 4.3?
Grok 4.3 is cheaper. It lists at $1.25 per million input tokens and $2.50 per million output tokens; Claude Fable 5 lists at $10 and $50.
Is Claude Fable 5 or Grok 4.3 better for coding?
Claude Fable 5 scores higher on coding benchmarks: 70.6 versus 41.6 in the Noometry coding category.
Which has the bigger context window?
Both accept 1M tokens.
How many benchmarks do Claude Fable 5 and Grok 4.3 share?
39 benchmarks have published results for both models. Claude Fable 5 has 62 scored results on Noometry and Grok 4.3 has 40.