Model comparison
Claude Sonnet 4.5 vs Hy4 preview
Hy4 preview is the stronger model overall, scoring 45.3 to 44.1 on the Noometry Index.
Last verified . 3 shared benchmarks.
Summary
- They share 3 benchmarks with published results for both. Claude Sonnet 4.5 scores higher in 0 categories and Hy4 preview in 3 categories; 3 gaps are clear of the uncertainty.
- The widest gap is in math, where Hy4 preview leads 55.7 to 32.3.
- The biggest single-benchmark swing is ProofBench: 19% for Claude Sonnet 4.5 and 75% for Hy4 preview.
- Hy4 preview is cheaper at $0.75 / $2.25 per million input/output tokens, against $3 / $15 for Claude Sonnet 4.5.
- Hy4 preview accepts more context: 1.05M tokens versus 200K.
- Hy4 preview has downloadable open weights; the other is API-only.
Side by side
| Claude Sonnet 4.5 | Hy4 preview | |
|---|---|---|
| Provider | Anthropic | Tencent |
| Noometry Index | 44.1 | 45.3 |
| Released | 2025-09-29 | 2026-08-28 |
| Weights | Proprietary | Open |
| Context window | 200K | 1.05M |
| Max output | 64K | 64K |
| Input $ / M tokens | $3 | $0.75 |
| Output $ / M tokens | $15 | $2.25 |
| Results tracked | 73 | 3 |
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Category by category
Coding Hy4 preview leads
Claude Sonnet 4.5: 47.3 (#61), Hy4 preview: 51.6 (#38)
| Benchmark | Claude Sonnet 4.5 | Hy4 preview |
|---|---|---|
| LMArena WebDev | 1393 | 1632 |
| SWE-bench Verified | 71.3% | — |
| SWE-bench Verified (bash only) | 71.4% | — |
| SWE-bench Multilingual | 67% | — |
| SciCode | 44.7% | — |
| GSO | 14.7% | — |
| WeirdML | 47.7% | — |
| LMArena Coding | 1489 | — |
| ALE-Bench | 796.15 | — |
| AlgoTune | 1.52 | — |
Agentic & Tool Use Not comparable
Claude Sonnet 4.5: 38.3 (#32), Hy4 preview: —
| Benchmark | Claude Sonnet 4.5 | Hy4 preview |
|---|---|---|
| Terminal-Bench | 46.5% | — |
| Berkeley Function Calling Leaderboard | 73.2% | — |
| GDPval | 42.5% | — |
| Remote Labor Index | 2.1% | — |
| τ²-bench Airline | 72% | — |
| τ²-bench Banking | 25.3% | — |
| τ²-bench Retail | 72.4% | — |
| τ²-bench Telecom | 84.9% | — |
| Cybench | 60% | — |
| DeepResearch Bench | 52.6% | — |
| OSWorld | 62.9% | — |
| LMArena Search | 1159 | — |
| METR Time Horizons | 67.4% | — |
| Vending-Bench 2 | 3,839 | — |
Reasoning Hy4 preview leads
Claude Sonnet 4.5: 26.9 (#125), Hy4 preview: 31.9 (#79)
| Benchmark | Claude Sonnet 4.5 | Hy4 preview |
|---|---|---|
| NYT Connections (extended) | 37.3% | 68.2% |
| ARC-AGI-2 | 13.6% | — |
| SimpleBench | 54.3% | — |
| Kagi LLM Benchmark | 57.9% | — |
| ARC-AGI-1 | 63.7% | — |
| CritPt | 1.1% | — |
| Chess Puzzles | 12% | — |
| EnigmaEval | 6% | — |
| EBR-Bench | 2.4% | — |
| LMArena Hard Prompts | 1462 | — |
| Mystery Game Puzzles | 17% | — |
| DTBench | 83.2% | — |
| LMCA | 38.8% | — |
| Epoch Capabilities Index | 146.84 | — |
| ForecastBench | 61.9 | — |
Math Hy4 preview leads
Claude Sonnet 4.5: 32.3 (#216), Hy4 preview: 55.7 (#42)
| Benchmark | Claude Sonnet 4.5 | Hy4 preview |
|---|---|---|
| ProofBench | 19% | 75% |
| FrontierMath (Tiers 1-3) | 23.9% | — |
| FrontierMath Tier 4 | 2.4% | — |
| OTIS Mock AIME 2024-2025 | 77.8% | — |
| Omni-MATH | 55.3% | — |
| LMArena Math | 1449 | — |
| MATH Level 5 | 97.7% | — |
| FrontierMath (Feb 2025 set) | 15.2% | — |
| FrontierMath Tier 4 (v1) | 4.2% | — |
Knowledge Not comparable
Claude Sonnet 4.5: 48.4 (#76), Hy4 preview: —
| Benchmark | Claude Sonnet 4.5 | Hy4 preview |
|---|---|---|
| GPQA Diamond | 82.3% | — |
| Humanity's Last Exam | 13.7% | — |
| SimpleQA Verified | 30.7% | — |
| MMLU-Pro | 86.9% | — |
| Vectara Hallucination Rate | 12% | — |
| GPQA (HELM) | 68.6% | — |
| LMArena Expert | 1482 | — |
Multimodal Not comparable
Claude Sonnet 4.5: 34.8 (#89), Hy4 preview: —
| Benchmark | Claude Sonnet 4.5 | Hy4 preview |
|---|---|---|
| VPCT | 39.8% | — |
| LMArena Document | 1450 | — |
Multilingual Not comparable
Claude Sonnet 4.5: 53.4 (#69), Hy4 preview: —
| Benchmark | Claude Sonnet 4.5 | Hy4 preview |
|---|---|---|
| LMArena Non-English | 1425 | — |
| LMArena Chinese | 1459 | — |
| LMArena French | 1458 | — |
| LMArena German | 1427 | — |
| LMArena Japanese | 1390 | — |
| LMArena Korean | 1403 | — |
| LMArena Russian | 1437 | — |
| LMArena Spanish | 1457 | — |
Instruction Following Not comparable
Claude Sonnet 4.5: 75.0 (#78), Hy4 preview: —
| Benchmark | Claude Sonnet 4.5 | Hy4 preview |
|---|---|---|
| IFEval | 85% | — |
| LMArena Instruction Following | 1459 | — |
Long Context Not comparable
Claude Sonnet 4.5: 45.2 (#46), Hy4 preview: —
| Benchmark | Claude Sonnet 4.5 | Hy4 preview |
|---|---|---|
| LMArena Longer Query | 1476 | — |
Writing & Preference Not comparable
Claude Sonnet 4.5: 66.5 (#34), Hy4 preview: —
| Benchmark | Claude Sonnet 4.5 | Hy4 preview |
|---|---|---|
| LMArena Text | 1439 | — |
| LMArena Creative Writing | 1442 | — |
| EQ-Bench Creative Writing | 1678 | — |
| WildBench | 85.4% | — |
| LMArena Multi-Turn | 1465 | — |
Frequently asked questions
Is Claude Sonnet 4.5 better than Hy4 preview?
Hy4 preview is the stronger model overall, scoring 45.3 to 44.1 on the Noometry Index.
Which is cheaper, Claude Sonnet 4.5 or Hy4 preview?
Hy4 preview is cheaper. It lists at $0.75 per million input tokens and $2.25 per million output tokens; Claude Sonnet 4.5 lists at $3 and $15.
Is Claude Sonnet 4.5 or Hy4 preview better for coding?
Hy4 preview scores higher on coding benchmarks: 51.6 versus 47.3 in the Noometry coding category.
Which has the bigger context window?
Hy4 preview does, with 1.05M tokens against 200K.
How many benchmarks do Claude Sonnet 4.5 and Hy4 preview share?
3 benchmarks have published results for both models. Claude Sonnet 4.5 has 73 scored results on Noometry and Hy4 preview has 3.