Model comparison
Claude Sonnet 5.5 vs Mercury
Claude Sonnet 5.5 is the stronger model overall, scoring 61.9 to 37.6 on the Noometry Index.
Last verified . 8 shared benchmarks.
Summary
- They share 8 benchmarks with published results for both. Claude Sonnet 5.5 scores higher in 6 categories and Mercury in 0 categories; 6 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where Claude Sonnet 5.5 leads 54.0 to 17.5.
Side by side
| Claude Sonnet 5.5 | Mercury | |
|---|---|---|
| Provider | Anthropic | Inception |
| Noometry Index | 61.9 | 37.6 |
| Released | 2026-09-28 | — |
| Weights | Proprietary | Proprietary |
| Context window | 1M | — |
| Max output | 128K | — |
| Input $ / M tokens | $2 | — |
| Output $ / M tokens | $10 | — |
| Results tracked | 32 | 9 |
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Category by category
Coding Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 67.3 (#6), Mercury: 38.7 (#170)
| Benchmark | Claude Sonnet 5.5 | Mercury |
|---|---|---|
| LMArena Coding | 1513 | 1322 |
| FrontierCode | 52.1% | — |
| CursorBench | 55.5% | — |
| LMArena WebDev | 1774 | — |
| FrontierSWE | 61.9% | — |
| SciCode | 61% | — |
| ALE-Bench | 1,819 | — |
Agentic & Tool Use Not comparable
Claude Sonnet 5.5: 45.0 (#16), Mercury: —
| Benchmark | Claude Sonnet 5.5 | Mercury |
|---|---|---|
| APEX-Agents | 75.5% | — |
Reasoning Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 54.0 (#28), Mercury: 17.5 (#293)
| Benchmark | Claude Sonnet 5.5 | Mercury |
|---|---|---|
| LMArena Hard Prompts | 1495 | 1285 |
| Kagi LLM Benchmark | — | 21.6% |
| NYT Connections (extended) | 80.5% | — |
| CritPt | 31.4% | — |
| Mystery Game Puzzles | 65% | — |
| Epoch Capabilities Index | 165.03 | — |
Math Not comparable
Claude Sonnet 5.5: 87.9 (#6), Mercury: —
| Benchmark | Claude Sonnet 5.5 | Mercury |
|---|---|---|
| FrontierMath (Tiers 1-3) | 88.8% | — |
| FrontierMath Tier 4 | 80.5% | — |
| OTIS Mock AIME 2024-2025 | 100% | — |
| ProofBench | 100% | — |
| LMArena Math | 1510 | — |
| FrontierMath Erdős | 2.9% | — |
Knowledge Not comparable
Claude Sonnet 5.5: 66.0 (#12), Mercury: —
| Benchmark | Claude Sonnet 5.5 | Mercury |
|---|---|---|
| GPQA Diamond | 95.6% | — |
| SimpleQA Verified | 46.5% | — |
| LMArena Expert | 1540 | — |
Multimodal Not comparable
Claude Sonnet 5.5: 51.5 (#6), Mercury: —
| Benchmark | Claude Sonnet 5.5 | Mercury |
|---|---|---|
| LMArena Vision | 1289 | — |
| Furniture Assembly | 75% | — |
Multilingual Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 55.3 (#30), Mercury: 41.6 (#206)
| Benchmark | Claude Sonnet 5.5 | Mercury |
|---|---|---|
| LMArena Non-English | 1452 | 1260 |
| LMArena Chinese | 1522 | — |
| LMArena Russian | 1451 | — |
Instruction Following Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 78.3 (#11), Mercury: 65.2 (#224)
| Benchmark | Claude Sonnet 5.5 | Mercury |
|---|---|---|
| LMArena Instruction Following | 1495 | 1239 |
Long Context Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 45.9 (#28), Mercury: 38.4 (#198)
| Benchmark | Claude Sonnet 5.5 | Mercury |
|---|---|---|
| LMArena Longer Query | 1498 | 1266 |
Writing & Preference Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 66.0 (#40), Mercury: 46.2 (#221)
| Benchmark | Claude Sonnet 5.5 | Mercury |
|---|---|---|
| LMArena Text | 1471 | 1282 |
| LMArena Creative Writing | 1465 | 1191 |
| LMArena Multi-Turn | 1474 | 1282 |
Frequently asked questions
Is Claude Sonnet 5.5 better than Mercury?
Claude Sonnet 5.5 is the stronger model overall, scoring 61.9 to 37.6 on the Noometry Index.
Is Claude Sonnet 5.5 or Mercury better for coding?
Claude Sonnet 5.5 scores higher on coding benchmarks: 67.3 versus 38.7 in the Noometry coding category.
How many benchmarks do Claude Sonnet 5.5 and Mercury share?
8 benchmarks have published results for both models. Claude Sonnet 5.5 has 32 scored results on Noometry and Mercury has 9.