Model comparison
Claude Sonnet 4.5 vs Muse Spark 1.2
Muse Spark 1.2 is the stronger model overall, scoring 49.8 to 44.0 on the Noometry Index.
Last verified . 23 shared benchmarks.
MetaSummary
- They share 23 benchmarks with published results for both. Claude Sonnet 4.5 scores higher in 1 category and Muse Spark 1.2 in 9 categories; 8 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where Muse Spark 1.2 leads 50.4 to 26.9.
- The biggest single-benchmark swing is NYT Connections (extended): 37.3% for Claude Sonnet 4.5 and 79.2% for Muse Spark 1.2.
- Muse Spark 1.2 is cheaper at $1.25 / $4.25 per million input/output tokens, against $3 / $15 for Claude Sonnet 4.5.
- Muse Spark 1.2 accepts more context: 1.05M tokens versus 1M.
Side by side
| Claude Sonnet 4.5 | Muse Spark 1.2 | |
|---|---|---|
| Provider | Anthropic | Meta |
| Noometry Index | 44.0 | 49.8 |
| Released | 2025-09-29 | 2026-08-05 |
| Weights | Proprietary | Proprietary |
| Context window | 1M | 1.05M |
| Max output | 64K | 131K |
| Input $ / M tokens | $3 | $1.25 |
| Output $ / M tokens | $15 | $4.25 |
| Results tracked | 73 | 28 |
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Category by category
Coding Too close to call
Claude Sonnet 4.5: 47.8 (#54), Muse Spark 1.2: 48.6 (#49)
| Benchmark | Claude Sonnet 4.5 | Muse Spark 1.2 |
|---|---|---|
| LMArena WebDev | 1393 | 1532 |
| SciCode | 44.7% | 56.4% |
| WeirdML | 47.7% | 60.3% |
| LMArena Coding | 1489 | 1497 |
| SWE-bench Verified | 71.3% | — |
| DeepSWE | — | 54.9% |
| SWE-bench Verified (bash only) | 71.4% | — |
| SWE-bench Multilingual | 67% | — |
| FrontierSWE | — | 12% |
| GSO | 14.7% | — |
| ALE-Bench | 796.15 | — |
| AlgoTune | 1.52 | — |
Agentic & Tool Use Claude Sonnet 4.5 leads
Claude Sonnet 4.5: 38.1 (#30), Muse Spark 1.2: 29.5 (#77)
| Benchmark | Claude Sonnet 4.5 | Muse Spark 1.2 |
|---|---|---|
| Terminal-Bench | 46.5% | — |
| APEX-Agents | — | 36.4% |
| 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% | — |
| GDP.pdf | — | 16% |
| LMArena Search | 1159 | — |
| METR Time Horizons | 67.4% | — |
| Vending-Bench 2 | 3,839 | — |
Reasoning Muse Spark 1.2 leads
Claude Sonnet 4.5: 26.9 (#113), Muse Spark 1.2: 50.4 (#32)
| Benchmark | Claude Sonnet 4.5 | Muse Spark 1.2 |
|---|---|---|
| SimpleBench | 54.3% | 74.5% |
| NYT Connections (extended) | 37.3% | 79.2% |
| CritPt | 1.1% | 17.7% |
| LMArena Hard Prompts | 1462 | 1490 |
| DTBench | 83.2% | 94.7% |
| LMCA | 38.8% | 48.4% |
| Epoch Capabilities Index | 146.84 | 155.18 |
| ARC-AGI-2 | 13.6% | — |
| Kagi LLM Benchmark | 57.9% | — |
| ARC-AGI-1 | 63.7% | — |
| Chess Puzzles | 12% | — |
| EnigmaEval | 6% | — |
| EBR-Bench | 2.4% | — |
| Mystery Game Puzzles | 17% | — |
| ForecastBench | 61.9 | — |
Math Muse Spark 1.2 leads
Claude Sonnet 4.5: 31.9 (#190), Muse Spark 1.2: 43.8 (#68)
| Benchmark | Claude Sonnet 4.5 | Muse Spark 1.2 |
|---|---|---|
| ProofBench | 19% | 43% |
| FrontierMath (Tiers 1-3) | 23.9% | — |
| FrontierMath Tier 4 | 2.4% | — |
| OTIS Mock AIME 2024-2025 | 77.8% | — |
| Omni-MATH | 55.3% | — |
| LMArena Math | 1448 | — |
| MATH Level 5 | 97.7% | — |
| FrontierMath (Feb 2025 set) | 15.2% | — |
| FrontierMath Tier 4 (v1) | 4.2% | — |
Knowledge Muse Spark 1.2 leads
Claude Sonnet 4.5: 48.4 (#70), Muse Spark 1.2: 53.9 (#49)
| Benchmark | Claude Sonnet 4.5 | Muse Spark 1.2 |
|---|---|---|
| SimpleQA Verified | 30.7% | 60.3% |
| LMArena Expert | 1483 | 1485 |
| GPQA Diamond | 82.3% | — |
| Humanity's Last Exam | 13.7% | — |
| MMLU-Pro | 86.9% | — |
| Vectara Hallucination Rate | 12% | — |
| GPQA (HELM) | 68.6% | — |
Multimodal Muse Spark 1.2 leads
Claude Sonnet 4.5: 34.1 (#84), Muse Spark 1.2: 42.6 (#24)
| Benchmark | Claude Sonnet 4.5 | Muse Spark 1.2 |
|---|---|---|
| LMArena Vision | — | 1304 |
| VPCT | 39.8% | — |
| LMArena Document | 1450 | — |
Multilingual Muse Spark 1.2 leads
Claude Sonnet 4.5: 53.6 (#65), Muse Spark 1.2: 57.4 (#10)
| Benchmark | Claude Sonnet 4.5 | Muse Spark 1.2 |
|---|---|---|
| LMArena Non-English | 1425 | 1479 |
| LMArena Chinese | 1459 | 1519 |
| LMArena Russian | 1436 | 1494 |
| LMArena French | 1459 | — |
| LMArena German | 1427 | — |
| LMArena Japanese | 1390 | — |
| LMArena Korean | 1403 | — |
| LMArena Spanish | 1457 | — |
Instruction Following Muse Spark 1.2 leads
Claude Sonnet 4.5: 75.2 (#74), Muse Spark 1.2: 77.1 (#30)
| Benchmark | Claude Sonnet 4.5 | Muse Spark 1.2 |
|---|---|---|
| LMArena Instruction Following | 1459 | 1466 |
| IFEval | 85% | — |
Long Context Too close to call
Claude Sonnet 4.5: 45.2 (#45), Muse Spark 1.2: 45.4 (#35)
| Benchmark | Claude Sonnet 4.5 | Muse Spark 1.2 |
|---|---|---|
| LMArena Longer Query | 1476 | 1483 |
Writing & Preference Muse Spark 1.2 leads
Claude Sonnet 4.5: 66.7 (#33), Muse Spark 1.2: 72.6 (#14)
| Benchmark | Claude Sonnet 4.5 | Muse Spark 1.2 |
|---|---|---|
| LMArena Text | 1439 | 1486 |
| LMArena Creative Writing | 1442 | 1444 |
| EQ-Bench Creative Writing | 1678 | 1840 |
| LMArena Multi-Turn | 1465 | 1504 |
| WildBench | 85.4% | — |
Frequently asked questions
Is Claude Sonnet 4.5 better than Muse Spark 1.2?
Muse Spark 1.2 is the stronger model overall, scoring 49.8 to 44.0 on the Noometry Index.
Which is cheaper, Claude Sonnet 4.5 or Muse Spark 1.2?
Muse Spark 1.2 is cheaper. It lists at $1.25 per million input tokens and $4.25 per million output tokens; Claude Sonnet 4.5 lists at $3 and $15.
Is Claude Sonnet 4.5 or Muse Spark 1.2 better for coding?
They score almost the same on coding (47.8 vs 48.6); test both on your own repository before choosing.
Which has the bigger context window?
Muse Spark 1.2 does, with 1.05M tokens against 1M.
How many benchmarks do Claude Sonnet 4.5 and Muse Spark 1.2 share?
23 benchmarks have published results for both models. Claude Sonnet 4.5 has 73 scored results on Noometry and Muse Spark 1.2 has 28.