Model comparison
Claude Haiku 5.5 vs Grok 4.1 Fast
Claude Haiku 5.5 is the stronger model overall, scoring 49.5 to 41.4 on the Noometry Index.
Last verified . 2 shared benchmarks.
Summary
- They share 2 benchmarks with published results for both. Claude Haiku 5.5 scores higher in 4 categories and Grok 4.1 Fast in 1 category; 5 gaps are clear of the uncertainty.
- The widest gap is in math, where Claude Haiku 5.5 leads 73.6 to 31.9.
- The biggest single-benchmark swing is NYT Connections (extended): 65.7% for Claude Haiku 5.5 and 87.4% for Grok 4.1 Fast.
- Claude Haiku 5.5 is cheaper at $0.10 / $0.50 per million input/output tokens, against $0.20 / $0.50 for Grok 4.1 Fast.
- Claude Haiku 5.5 accepts more context: 1M tokens versus 128K.
Side by side
| Claude Haiku 5.5 | Grok 4.1 Fast | |
|---|---|---|
| Provider | Anthropic | xAI |
| Noometry Index | 49.5 | 41.4 |
| Released | 2026-10-07 | 2025-06-27 |
| Weights | Proprietary | Proprietary |
| Context window | 1M | 128K |
| Max output | 128K | 30K |
| Input $ / M tokens | $0.10 | $0.20 |
| Output $ / M tokens | $0.50 | $0.50 |
| Results tracked | 9 | 32 |
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Category by category
Coding Claude Haiku 5.5 leads
Claude Haiku 5.5: 49.2 (#50), Grok 4.1 Fast: 34.1 (#245)
| Benchmark | Claude Haiku 5.5 | Grok 4.1 Fast |
|---|---|---|
| LMArena WebDev | 1587 | 1242 |
| LMArena Coding | — | 1411 |
| ALE-Bench | — | 394.93 |
Agentic & Tool Use Not comparable
Claude Haiku 5.5: —, Grok 4.1 Fast: 36.3 (#39)
| Benchmark | Claude Haiku 5.5 | Grok 4.1 Fast |
|---|---|---|
| Berkeley Function Calling Leaderboard | — | 69.6% |
| τ²-bench Banking | — | 13.1% |
| LMArena Search | — | 1171 |
| Vending-Bench 2 | — | 1,107 |
Reasoning Grok 4.1 Fast leads
Claude Haiku 5.5: 35.2 (#69), Grok 4.1 Fast: 43.4 (#49)
| Benchmark | Claude Haiku 5.5 | Grok 4.1 Fast |
|---|---|---|
| NYT Connections (extended) | 65.7% | 87.4% |
| SimpleBench | — | 56% |
| LMArena Hard Prompts | — | 1407 |
| Mystery Game Puzzles | 30% | — |
| DTBench | — | 87.7% |
| ForecastBench | — | 61 |
Math Claude Haiku 5.5 leads
Claude Haiku 5.5: 73.6 (#18), Grok 4.1 Fast: 31.9 (#221)
| Benchmark | Claude Haiku 5.5 | Grok 4.1 Fast |
|---|---|---|
| FrontierMath (Tiers 1-3) | 75.1% | — |
| FrontierMath Tier 4 | 46.3% | — |
| MathArena Final-Answer Competitions | — | 60.9% |
| OTIS Mock AIME 2024-2025 | 98.9% | — |
| ProofBench | — | 4% |
| LMArena Math | — | 1408 |
Knowledge Claude Haiku 5.5 leads
Claude Haiku 5.5: 50.8 (#70), Grok 4.1 Fast: 33.1 (#207)
| Benchmark | Claude Haiku 5.5 | Grok 4.1 Fast |
|---|---|---|
| GPQA Diamond | 89.6% | — |
| SimpleQA Verified | 23.8% | — |
| Vectara Hallucination Rate | — | 17.8% |
| LMArena Expert | — | 1399 |
Multimodal Claude Haiku 5.5 leads
Claude Haiku 5.5: 43.7 (#21), Grok 4.1 Fast: 37.0 (#76)
| Benchmark | Claude Haiku 5.5 | Grok 4.1 Fast |
|---|---|---|
| LMArena Vision | — | 1201 |
| Furniture Assembly | 47.5% | — |
Multilingual Not comparable
Claude Haiku 5.5: —, Grok 4.1 Fast: 51.0 (#114)
| Benchmark | Claude Haiku 5.5 | Grok 4.1 Fast |
|---|---|---|
| LMArena Non-English | — | 1391 |
| LMArena Chinese | — | 1441 |
| LMArena French | — | 1415 |
| LMArena German | — | 1404 |
| LMArena Japanese | — | 1349 |
| LMArena Korean | — | 1361 |
| LMArena Russian | — | 1387 |
| LMArena Spanish | — | 1413 |
Instruction Following Not comparable
Claude Haiku 5.5: —, Grok 4.1 Fast: 72.7 (#133)
| Benchmark | Claude Haiku 5.5 | Grok 4.1 Fast |
|---|---|---|
| LMArena Instruction Following | — | 1376 |
Long Context Not comparable
Claude Haiku 5.5: —, Grok 4.1 Fast: 42.4 (#126)
| Benchmark | Claude Haiku 5.5 | Grok 4.1 Fast |
|---|---|---|
| LMArena Longer Query | — | 1390 |
Writing & Preference Not comparable
Claude Haiku 5.5: —, Grok 4.1 Fast: 57.2 (#131)
| Benchmark | Claude Haiku 5.5 | Grok 4.1 Fast |
|---|---|---|
| LMArena Text | — | 1408 |
| LMArena Creative Writing | — | 1394 |
| EQ-Bench Creative Writing | — | 1327 |
| LMArena Multi-Turn | — | 1389 |
Frequently asked questions
Is Claude Haiku 5.5 better than Grok 4.1 Fast?
Claude Haiku 5.5 is the stronger model overall, scoring 49.5 to 41.4 on the Noometry Index.
Which is cheaper, Claude Haiku 5.5 or Grok 4.1 Fast?
Claude Haiku 5.5 is cheaper. It lists at $0.10 per million input tokens and $0.50 per million output tokens; Grok 4.1 Fast lists at $0.20 and $0.50.
Is Claude Haiku 5.5 or Grok 4.1 Fast better for coding?
Claude Haiku 5.5 scores higher on coding benchmarks: 49.2 versus 34.1 in the Noometry coding category.
Which has the bigger context window?
Claude Haiku 5.5 does, with 1M tokens against 128K.
How many benchmarks do Claude Haiku 5.5 and Grok 4.1 Fast share?
2 benchmarks have published results for both models. Claude Haiku 5.5 has 9 scored results on Noometry and Grok 4.1 Fast has 32.