Model comparison
Claude Sonnet 4.5 vs Mercury
Claude Sonnet 4.5 is the stronger model overall, scoring 44.1 to 37.6 on the Noometry Index.
Last verified . 9 shared benchmarks.
Summary
- They share 9 benchmarks with published results for both. Claude Sonnet 4.5 scores higher in 6 categories and Mercury in 0 categories; 6 gaps are clear of the uncertainty.
- The widest gap is in writing & preference, where Claude Sonnet 4.5 leads 66.5 to 46.2.
- The biggest single-benchmark swing is Kagi LLM Benchmark: 57.9% for Claude Sonnet 4.5 and 21.6% for Mercury.
Side by side
| Claude Sonnet 4.5 | Mercury | |
|---|---|---|
| Provider | Anthropic | Inception |
| Noometry Index | 44.1 | 37.6 |
| Released | 2025-09-29 | — |
| Weights | Proprietary | Proprietary |
| Context window | 200K | — |
| Max output | 64K | — |
| Input $ / M tokens | $3 | — |
| Output $ / M tokens | $15 | — |
| Results tracked | 73 | 9 |
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Category by category
Coding Claude Sonnet 4.5 leads
Claude Sonnet 4.5: 47.3 (#61), Mercury: 38.7 (#170)
| Benchmark | Claude Sonnet 4.5 | Mercury |
|---|---|---|
| LMArena Coding | 1489 | 1322 |
| SWE-bench Verified | 71.3% | — |
| SWE-bench Verified (bash only) | 71.4% | — |
| LMArena WebDev | 1393 | — |
| SWE-bench Multilingual | 67% | — |
| SciCode | 44.7% | — |
| GSO | 14.7% | — |
| WeirdML | 47.7% | — |
| ALE-Bench | 796.15 | — |
| AlgoTune | 1.52 | — |
Agentic & Tool Use Not comparable
Claude Sonnet 4.5: 38.3 (#32), Mercury: —
| Benchmark | Claude Sonnet 4.5 | Mercury |
|---|---|---|
| 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 Claude Sonnet 4.5 leads
Claude Sonnet 4.5: 26.9 (#125), Mercury: 17.5 (#293)
| Benchmark | Claude Sonnet 4.5 | Mercury |
|---|---|---|
| Kagi LLM Benchmark | 57.9% | 21.6% |
| LMArena Hard Prompts | 1462 | 1285 |
| ARC-AGI-2 | 13.6% | — |
| SimpleBench | 54.3% | — |
| NYT Connections (extended) | 37.3% | — |
| ARC-AGI-1 | 63.7% | — |
| CritPt | 1.1% | — |
| Chess Puzzles | 12% | — |
| EnigmaEval | 6% | — |
| EBR-Bench | 2.4% | — |
| Mystery Game Puzzles | 17% | — |
| DTBench | 83.2% | — |
| LMCA | 38.8% | — |
| Epoch Capabilities Index | 146.84 | — |
| ForecastBench | 61.9 | — |
Math Not comparable
Claude Sonnet 4.5: 32.3 (#216), Mercury: —
| Benchmark | Claude Sonnet 4.5 | Mercury |
|---|---|---|
| FrontierMath (Tiers 1-3) | 23.9% | — |
| FrontierMath Tier 4 | 2.4% | — |
| OTIS Mock AIME 2024-2025 | 77.8% | — |
| ProofBench | 19% | — |
| 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), Mercury: —
| Benchmark | Claude Sonnet 4.5 | Mercury |
|---|---|---|
| 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), Mercury: —
| Benchmark | Claude Sonnet 4.5 | Mercury |
|---|---|---|
| VPCT | 39.8% | — |
| LMArena Document | 1450 | — |
Multilingual Claude Sonnet 4.5 leads
Claude Sonnet 4.5: 53.4 (#69), Mercury: 41.6 (#206)
| Benchmark | Claude Sonnet 4.5 | Mercury |
|---|---|---|
| LMArena Non-English | 1425 | 1260 |
| LMArena Chinese | 1459 | — |
| LMArena French | 1458 | — |
| LMArena German | 1427 | — |
| LMArena Japanese | 1390 | — |
| LMArena Korean | 1403 | — |
| LMArena Russian | 1437 | — |
| LMArena Spanish | 1457 | — |
Instruction Following Claude Sonnet 4.5 leads
Claude Sonnet 4.5: 75.0 (#78), Mercury: 65.2 (#224)
| Benchmark | Claude Sonnet 4.5 | Mercury |
|---|---|---|
| LMArena Instruction Following | 1459 | 1239 |
| IFEval | 85% | — |
Long Context Claude Sonnet 4.5 leads
Claude Sonnet 4.5: 45.2 (#46), Mercury: 38.4 (#198)
| Benchmark | Claude Sonnet 4.5 | Mercury |
|---|---|---|
| LMArena Longer Query | 1476 | 1266 |
Writing & Preference Claude Sonnet 4.5 leads
Claude Sonnet 4.5: 66.5 (#34), Mercury: 46.2 (#221)
| Benchmark | Claude Sonnet 4.5 | Mercury |
|---|---|---|
| LMArena Text | 1439 | 1282 |
| LMArena Creative Writing | 1442 | 1191 |
| LMArena Multi-Turn | 1465 | 1282 |
| EQ-Bench Creative Writing | 1678 | — |
| WildBench | 85.4% | — |
Frequently asked questions
Is Claude Sonnet 4.5 better than Mercury?
Claude Sonnet 4.5 is the stronger model overall, scoring 44.1 to 37.6 on the Noometry Index.
Is Claude Sonnet 4.5 or Mercury better for coding?
Claude Sonnet 4.5 scores higher on coding benchmarks: 47.3 versus 38.7 in the Noometry coding category.
How many benchmarks do Claude Sonnet 4.5 and Mercury share?
9 benchmarks have published results for both models. Claude Sonnet 4.5 has 73 scored results on Noometry and Mercury has 9.