Model comparison
Claude Sonnet 5.5 vs Gemini 2.5 Flash-Lite
Claude Sonnet 5.5 is the stronger model overall, scoring 61.9 to 37.0 on the Noometry Index. Gemini 2.5 Flash-Lite costs 23× less per token, which makes it the better buy when Claude Sonnet 5.5's lead doesn't matter for your workload.
Last verified . 15 shared benchmarks.
GoogleSummary
- They share 15 benchmarks with published results for both. Claude Sonnet 5.5 scores higher in 10 categories and Gemini 2.5 Flash-Lite in 0 categories; 10 gaps are clear of the uncertainty.
- The widest gap is in math, where Claude Sonnet 5.5 leads 87.9 to 38.0.
- Gemini 2.5 Flash-Lite is cheaper at $0.10 / $0.40 per million input/output tokens, against $2 / $10 for Claude Sonnet 5.5.
- Gemini 2.5 Flash-Lite accepts more context: 1.05M tokens versus 1M.
Side by side
| Claude Sonnet 5.5 | Gemini 2.5 Flash-Lite | |
|---|---|---|
| Provider | Anthropic | |
| Noometry Index | 61.9 | 37.0 |
| Released | 2026-09-28 | 2025-06-17 |
| Weights | Proprietary | Proprietary |
| Context window | 1M | 1.05M |
| Max output | 128K | 66K |
| Input $ / M tokens | $2 | $0.10 |
| Output $ / M tokens | $10 | $0.40 |
| Results tracked | 32 | 33 |
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Category by category
Coding Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 67.3 (#6), Gemini 2.5 Flash-Lite: 38.5 (#173)
| Benchmark | Claude Sonnet 5.5 | Gemini 2.5 Flash-Lite |
|---|---|---|
| LMArena Coding | 1513 | 1373 |
| ALE-Bench | 1,819 | 325.9 |
| FrontierCode | 52.1% | — |
| CursorBench | 55.5% | — |
| LMArena WebDev | 1774 | — |
| FrontierSWE | 61.9% | — |
| SciCode | 61% | — |
| WeirdML | — | 35.2% |
Agentic & Tool Use Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 45.0 (#16), Gemini 2.5 Flash-Lite: 28.0 (#96)
| Benchmark | Claude Sonnet 5.5 | Gemini 2.5 Flash-Lite |
|---|---|---|
| APEX-Agents | 75.5% | — |
| Berkeley Function Calling Leaderboard | — | 36.9% |
Reasoning Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 54.0 (#28), Gemini 2.5 Flash-Lite: 22.2 (#205)
| Benchmark | Claude Sonnet 5.5 | Gemini 2.5 Flash-Lite |
|---|---|---|
| LMArena Hard Prompts | 1495 | 1377 |
| Epoch Capabilities Index | 165.03 | 133.94 |
| Kagi LLM Benchmark | — | 40.5% |
| NYT Connections (extended) | 80.5% | — |
| CritPt | 31.4% | — |
| Mystery Game Puzzles | 65% | — |
| DTBench | — | 62.8% |
| LMCA | — | 18.1% |
Math Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 87.9 (#6), Gemini 2.5 Flash-Lite: 38.0 (#144)
| Benchmark | Claude Sonnet 5.5 | Gemini 2.5 Flash-Lite |
|---|---|---|
| LMArena Math | 1510 | 1373 |
| FrontierMath (Tiers 1-3) | 88.8% | — |
| FrontierMath Tier 4 | 80.5% | — |
| OTIS Mock AIME 2024-2025 | 100% | — |
| ProofBench | 100% | — |
| Omni-MATH | — | 48% |
| FrontierMath Erdős | 2.9% | — |
Knowledge Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 66.0 (#12), Gemini 2.5 Flash-Lite: 32.5 (#210)
| Benchmark | Claude Sonnet 5.5 | Gemini 2.5 Flash-Lite |
|---|---|---|
| LMArena Expert | 1540 | 1373 |
| GPQA Diamond | 95.6% | — |
| SimpleQA Verified | 46.5% | — |
| MMLU-Pro | — | 53.7% |
| Vectara Hallucination Rate | — | 3.3% |
| GPQA (HELM) | — | 30.9% |
Multimodal Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 51.5 (#6), Gemini 2.5 Flash-Lite: 29.1 (#114)
| Benchmark | Claude Sonnet 5.5 | Gemini 2.5 Flash-Lite |
|---|---|---|
| LMArena Vision | 1289 | 1198 |
| VPCT | — | 30% |
| Furniture Assembly | 75% | — |
Multilingual Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 55.3 (#30), Gemini 2.5 Flash-Lite: 49.3 (#134)
| Benchmark | Claude Sonnet 5.5 | Gemini 2.5 Flash-Lite |
|---|---|---|
| LMArena Non-English | 1452 | 1369 |
| LMArena Chinese | 1522 | 1404 |
| LMArena Russian | 1451 | 1373 |
| LMArena French | — | 1388 |
| LMArena German | — | 1389 |
| LMArena Japanese | — | 1359 |
| LMArena Korean | — | 1360 |
| LMArena Spanish | — | 1396 |
Instruction Following Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 78.3 (#11), Gemini 2.5 Flash-Lite: 70.0 (#168)
| Benchmark | Claude Sonnet 5.5 | Gemini 2.5 Flash-Lite |
|---|---|---|
| LMArena Instruction Following | 1495 | 1367 |
| IFEval | — | 81% |
Long Context Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 45.9 (#28), Gemini 2.5 Flash-Lite: 33.3 (#262)
| Benchmark | Claude Sonnet 5.5 | Gemini 2.5 Flash-Lite |
|---|---|---|
| LMArena Longer Query | 1498 | 1373 |
| Fiction.LiveBench | — | 47.2% |
Writing & Preference Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 66.0 (#40), Gemini 2.5 Flash-Lite: 56.8 (#135)
| Benchmark | Claude Sonnet 5.5 | Gemini 2.5 Flash-Lite |
|---|---|---|
| LMArena Text | 1471 | 1379 |
| LMArena Creative Writing | 1465 | 1367 |
| LMArena Multi-Turn | 1474 | 1366 |
| WildBench | — | 81.8% |
Frequently asked questions
Is Claude Sonnet 5.5 better than Gemini 2.5 Flash-Lite?
Claude Sonnet 5.5 is the stronger model overall, scoring 61.9 to 37.0 on the Noometry Index. Gemini 2.5 Flash-Lite costs 23× less per token, which makes it the better buy when Claude Sonnet 5.5's lead doesn't matter for your workload.
Which is cheaper, Claude Sonnet 5.5 or Gemini 2.5 Flash-Lite?
Gemini 2.5 Flash-Lite is cheaper. It lists at $0.10 per million input tokens and $0.40 per million output tokens; Claude Sonnet 5.5 lists at $2 and $10.
Is Claude Sonnet 5.5 or Gemini 2.5 Flash-Lite better for coding?
Claude Sonnet 5.5 scores higher on coding benchmarks: 67.3 versus 38.5 in the Noometry coding category.
Which has the bigger context window?
Gemini 2.5 Flash-Lite does, with 1.05M tokens against 1M.
How many benchmarks do Claude Sonnet 5.5 and Gemini 2.5 Flash-Lite share?
15 benchmarks have published results for both models. Claude Sonnet 5.5 has 32 scored results on Noometry and Gemini 2.5 Flash-Lite has 33.