Model comparison
Claude Sonnet 5.5 vs Gemini 3.5 Flash
Claude Sonnet 5.5 is the stronger model overall, scoring 61.9 to 54.2 on the Noometry Index.
Last verified . 27 shared benchmarks.
GoogleSummary
- They share 27 benchmarks with published results for both. Claude Sonnet 5.5 scores higher in 7 categories and Gemini 3.5 Flash in 3 categories; 7 gaps are clear of the uncertainty.
- The widest gap is in math, where Claude Sonnet 5.5 leads 87.9 to 60.7.
- The biggest single-benchmark swing is ProofBench: 100% for Claude Sonnet 5.5 and 31% for Gemini 3.5 Flash.
- Gemini 3.5 Flash is cheaper at $1.50 / $9 per million input/output tokens, against $2 / $10 for Claude Sonnet 5.5.
- Gemini 3.5 Flash accepts more context: 1.05M tokens versus 1M.
Side by side
| Claude Sonnet 5.5 | Gemini 3.5 Flash | |
|---|---|---|
| Provider | Anthropic | |
| Noometry Index | 61.9 | 54.2 |
| Released | 2026-09-28 | 2026-05-19 |
| Weights | Proprietary | Proprietary |
| Context window | 1M | 1.05M |
| Max output | 128K | 66K |
| Input $ / M tokens | $2 | $1.50 |
| Output $ / M tokens | $10 | $9 |
| Results tracked | 32 | 54 |
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Category by category
Coding Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 67.3 (#6), Gemini 3.5 Flash: 49.4 (#49)
| Benchmark | Claude Sonnet 5.5 | Gemini 3.5 Flash |
|---|---|---|
| LMArena WebDev | 1774 | 1499 |
| SciCode | 61% | 53.1% |
| LMArena Coding | 1513 | 1492 |
| ALE-Bench | 1,819 | 911.02 |
| SWE-bench Verified | — | 79.3% |
| DeepSWE | — | 37.4% |
| FrontierCode | 52.1% | — |
| CursorBench | 55.5% | — |
| FrontierSWE | 61.9% | — |
| WeirdML | — | 62.6% |
Agentic & Tool Use Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 45.0 (#16), Gemini 3.5 Flash: 24.7 (#114)
| Benchmark | Claude Sonnet 5.5 | Gemini 3.5 Flash |
|---|---|---|
| APEX-Agents | 75.5% | 27.5% |
| GBAEval | — | 6.7% |
| GDP.pdf | — | 14% |
| Vending-Bench 2 | — | 5,396 |
Reasoning Gemini 3.5 Flash leads
Claude Sonnet 5.5: 54.0 (#28), Gemini 3.5 Flash: 62.8 (#18)
| Benchmark | Claude Sonnet 5.5 | Gemini 3.5 Flash |
|---|---|---|
| NYT Connections (extended) | 80.5% | 92.6% |
| CritPt | 31.4% | 13.1% |
| LMArena Hard Prompts | 1495 | 1488 |
| Mystery Game Puzzles | 65% | 32% |
| Epoch Capabilities Index | 165.03 | 154.46 |
| ARC-AGI-2 | — | 72.1% |
| SimpleBench | — | 76.7% |
| ARC-AGI-1 | — | 92.5% |
| Chess Puzzles | — | 50% |
| EnigmaEval | — | 25.4% |
| EBR-Bench | — | 4.8% |
| DTBench | — | 94.7% |
| LMCA | — | 47.1% |
| Surface Evolver Bench | — | 58.1% |
| ForecastBench | — | 59 |
Math Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 87.9 (#6), Gemini 3.5 Flash: 60.7 (#36)
| Benchmark | Claude Sonnet 5.5 | Gemini 3.5 Flash |
|---|---|---|
| FrontierMath (Tiers 1-3) | 88.8% | 62.8% |
| FrontierMath Tier 4 | 80.5% | 26.8% |
| OTIS Mock AIME 2024-2025 | 100% | 95.6% |
| ProofBench | 100% | 31% |
| LMArena Math | 1510 | 1504 |
| MathArena Final-Answer Competitions | — | 76.3% |
| FrontierMath (Feb 2025 set) | — | 39% |
| FrontierMath Erdős | 2.9% | — |
| FrontierMath Tier 4 (v1) | — | 14.6% |
Knowledge Too close to call
Claude Sonnet 5.5: 66.0 (#12), Gemini 3.5 Flash: 66.3 (#11)
| Benchmark | Claude Sonnet 5.5 | Gemini 3.5 Flash |
|---|---|---|
| GPQA Diamond | 95.6% | 92.8% |
| SimpleQA Verified | 46.5% | 66.2% |
| LMArena Expert | 1540 | 1495 |
Multimodal Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 51.5 (#6), Gemini 3.5 Flash: 45.7 (#15)
| Benchmark | Claude Sonnet 5.5 | Gemini 3.5 Flash |
|---|---|---|
| LMArena Vision | 1289 | 1310 |
| Blueprint-Bench 2 | — | 33.6% |
| Furniture Assembly | 75% | — |
| LMArena Document | — | 1463 |
Multilingual Gemini 3.5 Flash leads
Claude Sonnet 5.5: 55.3 (#30), Gemini 3.5 Flash: 57.0 (#13)
| Benchmark | Claude Sonnet 5.5 | Gemini 3.5 Flash |
|---|---|---|
| LMArena Non-English | 1452 | 1476 |
| LMArena Chinese | 1522 | 1526 |
| LMArena Russian | 1451 | 1493 |
| LMArena French | — | 1490 |
| LMArena German | — | 1492 |
| LMArena Japanese | — | 1486 |
| LMArena Korean | — | 1451 |
| LMArena Spanish | — | 1480 |
Instruction Following Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 78.3 (#11), Gemini 3.5 Flash: 77.0 (#30)
| Benchmark | Claude Sonnet 5.5 | Gemini 3.5 Flash |
|---|---|---|
| LMArena Instruction Following | 1495 | 1467 |
Long Context Too close to call
Claude Sonnet 5.5: 45.9 (#28), Gemini 3.5 Flash: 45.4 (#38)
| Benchmark | Claude Sonnet 5.5 | Gemini 3.5 Flash |
|---|---|---|
| LMArena Longer Query | 1498 | 1482 |
Writing & Preference Too close to call
Claude Sonnet 5.5: 66.0 (#40), Gemini 3.5 Flash: 65.5 (#47)
| Benchmark | Claude Sonnet 5.5 | Gemini 3.5 Flash |
|---|---|---|
| LMArena Text | 1471 | 1482 |
| LMArena Creative Writing | 1465 | 1470 |
| LMArena Multi-Turn | 1474 | 1481 |
| EQ-Bench 4 | — | 1087 |
Frequently asked questions
Is Claude Sonnet 5.5 better than Gemini 3.5 Flash?
Claude Sonnet 5.5 is the stronger model overall, scoring 61.9 to 54.2 on the Noometry Index.
Which is cheaper, Claude Sonnet 5.5 or Gemini 3.5 Flash?
Gemini 3.5 Flash is cheaper. It lists at $1.50 per million input tokens and $9 per million output tokens; Claude Sonnet 5.5 lists at $2 and $10.
Is Claude Sonnet 5.5 or Gemini 3.5 Flash better for coding?
Claude Sonnet 5.5 scores higher on coding benchmarks: 67.3 versus 49.4 in the Noometry coding category.
Which has the bigger context window?
Gemini 3.5 Flash does, with 1.05M tokens against 1M.
How many benchmarks do Claude Sonnet 5.5 and Gemini 3.5 Flash share?
27 benchmarks have published results for both models. Claude Sonnet 5.5 has 32 scored results on Noometry and Gemini 3.5 Flash has 54.