Claude Sonnet 5.5 vs Gemini 3.1 Flash Lite Preview
Claude Sonnet 5.5 leads Gemini 3.1 Flash Lite Preview on coding, 87.3 to 22.7 on the Vibe Coding Index, and Gemini 3.1 Flash Lite Preview costs 6.7x less per output token ($1.50 vs $10.00 per million). Updated October 22, 2026; 54 benchmarks have a result for both.
Claude Sonnet 5.5 or Gemini 3.1 Flash Lite Preview: which to pick
Pick Claude Sonnet 5.5 for coding: it scores 87.3 on the Vibe Coding Index against 22.7 for Gemini 3.1 Flash Lite Preview.
Pick Gemini 3.1 Flash Lite Preview for output tokens 6.7x cheaper ($1.50 vs $10.00 per million) and a larger context window (1.05M against 1M tokens).
- Shared results
- 54
- Claude Sonnet 5.5 only
- 42
- Gemini 3.1 Flash Lite Preview only
- 25
- Like-for-like categories
- 8 of 9
Only benchmarks that tested both models count toward a pick; a result only one model has is shown but not compared.
Which one for your work
Each card is decided by one number both models carry. Where only one has it, the card says so and makes no call.
Coding
Vibe Coding Index, six public coding benchmarks
Claude Sonnet 5.5
Claude Sonnet 5.5 scores 87.3 against 22.7.
5 and 3 benchmarks behind the scores
Intelligence
AA Intelligence Index
Claude Sonnet 5.5
Claude Sonnet 5.5 leads, 56.0 against 15.6.
Same board, both measured
Agentic work
AA Agentic Index
No call
Only Gemini 3.1 Flash Lite Preview has a AA Agentic Index result, 1.6.
Directional only
Reasoning
GPQA Diamond
No call
Only Gemini 3.1 Flash Lite Preview has a GPQA Diamond result, 81.1%.
Directional only
Math
AIME
No call
Only Gemini 3.1 Flash Lite Preview has a AIME result, 83.3%.
Directional only
Knowledge
MMLU Pro
No call
Only Gemini 3.1 Flash Lite Preview has a MMLU Pro result, 86.2%.
Directional only
Web design
Design Arena: websites
Claude Sonnet 5.5
Claude Sonnet 5.5 leads, 1326 against 1082.
Same board, both measured
General
Vals Index
No call
Only Claude Sonnet 5.5 has a Vals Index result, 70.8%.
Directional only
Long documents
Listed context window
Gemini 3.1 Flash Lite Preview
Gemini 3.1 Flash Lite Preview takes 1.05M tokens against 1M.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Gemini 3.1 Flash Lite Preview
Claude Sonnet 5.5 $0.0070, Gemini 3.1 Flash Lite Preview $0.0010 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
No call
Only Gemini 3.1 Flash Lite Preview has the number, $0.18.
Directional only
At a glance
- Coding index
- Claude Sonnet 5.5 87.3 from 5 benchmarks, Gemini 3.1 Flash Lite Preview 22.7 from 3 benchmarks.
- Widest category
- Agentic work, 44.7 points apart on average over 4 shared benchmarks.
- Widest single gap
- Vibe Code Bench (Vals AI): Claude Sonnet 5.5 92.4% against Gemini 3.1 Flash Lite Preview 0.0%, 92.4 points apart on a 0 to 100 scale.
- Output price
- Claude Sonnet 5.5 $10.00 against Gemini 3.1 Flash Lite Preview $1.50 per million output tokens, 6.7x apart.
- Context window
- Claude Sonnet 5.5 takes 1M tokens, Gemini 3.1 Flash Lite Preview 1.05M.
Benchmark by benchmark
First the score: boards each model leads, per category, where both have a result. Then every board, a category to a fold; bars are each result on a 0 to 100 scale, so compare the two in a row, not one row with another.
| Category | Claude Sonnet 5.5 | Bars | Gemini 3.1 Flash Lite Preview | Ties |
|---|---|---|---|---|
| Coding | 12 | 0 | ||
| Intelligence | 1 | 0 | ||
| Agentic work | 4 | 0 | ||
| Reasoning | 5 | 0 | ||
| Math | 2 | 0 | ||
| Knowledge | 5 | 0 | ||
| Web design | 6 | 0 | ||
| General | 18 | 1 | ||
| All shared boards | 53 | 1 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index120
| Benchmark | Claude Sonnet 5.5 | Gemini 3.1 Flash Lite Preview | Leader |
|---|---|---|---|
| LiveBench coding | 94.7% | Not measured | Only Claude Sonnet 5.5 measured |
| LMArena WebDev | 1768 | 1257 | Claude Sonnet 5.5 |
| AA Coding Index | Not measured | 34.7 | Only Gemini 3.1 Flash Lite Preview measured |
| LiveCodeBench (Vals AI) | Not measured | 80.1% | Only Gemini 3.1 Flash Lite Preview measured |
| SWE-bench Verified (Vals AI) | Not measured | 62.8% | Only Gemini 3.1 Flash Lite Preview measured |
| Terminal-Bench 4 (Vals AI) | 64.1% | Not measured | Only Claude Sonnet 5.5 measured |
| Vibe Code Bench (Vals AI) | 92.4% | 0.0% | Claude Sonnet 5.5 |
| Code migration (Vals AI) | 69.8% | 4.6% | Claude Sonnet 5.5 |
| ProgramBench (Vals AI) | 6.5% | 0.0% | Claude Sonnet 5.5 |
| IOI (Vals AI) | 83.1% | Not measured | Only Claude Sonnet 5.5 measured |
| Terminal-Bench 2.1 (Vals AI) | 83.2% | 34.1% | Claude Sonnet 5.5 |
| SWE-bench Multimodal (Vals AI) | 58.3% | Not measured | Only Claude Sonnet 5.5 measured |
| CyberBench (Vals AI) | 59.6% | Not measured | Only Claude Sonnet 5.5 measured |
| SciCode | 61.0% | Not measured | Only Claude Sonnet 5.5 measured |
| FrontierCode | 52.1% | Not measured | Only Claude Sonnet 5.5 measured |
| FrontierSWE | 61.9% | Not measured | Only Claude Sonnet 5.5 measured |
| ALE-Bench | 1819.1 | 797.7 | Claude Sonnet 5.5 |
| LMArena Text: coding | 1513 | 1400 | Claude Sonnet 5.5 |
| LMArena Text: software and IT | 1504 | 1413 | Claude Sonnet 5.5 |
| LMArena WebDev: React | 1817 | 1245 | Claude Sonnet 5.5 |
| LMArena WebDev: HTML | 1741 | 1276 | Claude Sonnet 5.5 |
| LMArena WebDev: from an image | 1737 | 1336 | Claude Sonnet 5.5 |
| SciCode | 13.8% | 4.6% | Claude Sonnet 5.5 |
| Neither model has a result on the other 16 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index10
| Benchmark | Claude Sonnet 5.5 | Gemini 3.1 Flash Lite Preview | Leader |
|---|---|---|---|
| AA Intelligence Index | 56.0 | 15.6 | Claude Sonnet 5.5 |
| Epoch Capabilities Index | 166.2 | Not measured | Only Claude Sonnet 5.5 measured |
Agentic workLike-for-likePublic boards, shown as published, kept out of the index40
| Benchmark | Claude Sonnet 5.5 | Gemini 3.1 Flash Lite Preview | Leader |
|---|---|---|---|
| AA Agentic Index | Not measured | 1.6 | Only Gemini 3.1 Flash Lite Preview measured |
| Design Arena: agents building web apps | 1305 | Not measured | Only Claude Sonnet 5.5 measured |
| Design Arena: agents building mobile apps | 1260 | Not measured | Only Claude Sonnet 5.5 measured |
| Design Arena: spreadsheets | 1260 | Not measured | Only Claude Sonnet 5.5 measured |
| LiveBench research | 83.6% | Not measured | Only Claude Sonnet 5.5 measured |
| LiveBench browser | 84.0% | Not measured | Only Claude Sonnet 5.5 measured |
| LiveBench long agentic | 78.8% | Not measured | Only Claude Sonnet 5.5 measured |
| SREBench (Vals AI) | 30.1% | Not measured | Only Claude Sonnet 5.5 measured |
| Finance Agent (Vals AI) | 58.1% | 30.0% | Claude Sonnet 5.5 |
| Tax Agent Bench (Vals AI) | 42.0% | 3.1% | Claude Sonnet 5.5 |
| Legal Research Bench (Vals AI) | 48.1% | 3.4% | Claude Sonnet 5.5 |
| Harvey's Legal Agent Benchmark (Vals AI) | 10.4% | Not measured | Only Claude Sonnet 5.5 measured |
| Excel Modeling Benchmark (Vals AI) | 75.7% | 8.6% | Claude Sonnet 5.5 |
| BioMysteryBench (Vals AI) | 81.1% | Not measured | Only Claude Sonnet 5.5 measured |
| Terminal-Bench-Science (Vals AI) | 47.1% | Not measured | Only Claude Sonnet 5.5 measured |
| Vals Science Index | 59.1% | Not measured | Only Claude Sonnet 5.5 measured |
| APEX-Agents | 75.5% | Not measured | Only Claude Sonnet 5.5 measured |
| SpireClimb | 1.3% | Not measured | Only Claude Sonnet 5.5 measured |
| Vending-Bench 2 | $11,165 | Not measured | Only Claude Sonnet 5.5 measured |
| Neither model has a result on the other 22 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index50
| Benchmark | Claude Sonnet 5.5 | Gemini 3.1 Flash Lite Preview | Leader |
|---|---|---|---|
| GPQA Diamond | Not measured | 81.1% | Only Gemini 3.1 Flash Lite Preview measured |
| LiveBench reasoning | 91.6% | Not measured | Only Claude Sonnet 5.5 measured |
| MysteryMechanism (Vals AI) | 49.1% | Not measured | Only Claude Sonnet 5.5 measured |
| MMMU Pro (Vals AI) | Not measured | 82.5% | Only Gemini 3.1 Flash Lite Preview measured |
| Humanity's Last Exam (Artificial Analysis run) | 55.0% | Not measured | Only Claude Sonnet 5.5 measured |
| GPQA Diamond (Epoch AI run) | 95.6% | Not measured | Only Claude Sonnet 5.5 measured |
| Chess puzzles | 59.0% | Not measured | Only Claude Sonnet 5.5 measured |
| Mystery game puzzles | 65.0% | Not measured | Only Claude Sonnet 5.5 measured |
| LMArena Text: hard prompts | 1494 | 1407 | Claude Sonnet 5.5 |
| LMArena Text: expert | 1531 | 1398 | Claude Sonnet 5.5 |
| LMArena Text: hard prompts in English | 1502 | 1403 | Claude Sonnet 5.5 |
| LMArena Vision: diagrams | 1329 | 1242 | Claude Sonnet 5.5 |
| LMArena Vision: homework | 1331 | 1271 | Claude Sonnet 5.5 |
| Neither model has a result on the other 9 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index20
| Benchmark | Claude Sonnet 5.5 | Gemini 3.1 Flash Lite Preview | Leader |
|---|---|---|---|
| AIME | Not measured | 83.3% | Only Gemini 3.1 Flash Lite Preview measured |
| OTIS Mock AIME | 100.0% | Not measured | Only Claude Sonnet 5.5 measured |
| FrontierMath, tiers 1 to 3 | 88.8% | Not measured | Only Claude Sonnet 5.5 measured |
| FrontierMath, tier 4 | 80.5% | Not measured | Only Claude Sonnet 5.5 measured |
| ProofBench | 100.0% | Not measured | Only Claude Sonnet 5.5 measured |
| LMArena Text: math | 1497 | 1428 | Claude Sonnet 5.5 |
| LMArena Text: mathematical work | 1510 | 1417 | Claude Sonnet 5.5 |
| Neither model has a result on the other 6 boards here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index50
| Benchmark | Claude Sonnet 5.5 | Gemini 3.1 Flash Lite Preview | Leader |
|---|---|---|---|
| MMLU Pro | Not measured | 86.2% | Only Gemini 3.1 Flash Lite Preview measured |
| LegalBench (Vals AI) | Not measured | 83.8% | Only Gemini 3.1 Flash Lite Preview measured |
| CaseLaw (Vals AI) | Not measured | 55.0% | Only Gemini 3.1 Flash Lite Preview measured |
| CorpFin (Vals AI) | Not measured | 59.4% | Only Gemini 3.1 Flash Lite Preview measured |
| TaxEval (Vals AI) | Not measured | 71.8% | Only Gemini 3.1 Flash Lite Preview measured |
| MortgageTax (Vals AI) | Not measured | 68.0% | Only Gemini 3.1 Flash Lite Preview measured |
| MedCode (Vals AI) | 52.9% | 47.6% | Claude Sonnet 5.5 |
| SimpleQA Verified | 46.5% | Not measured | Only Claude Sonnet 5.5 measured |
| LMArena Text: science | 1483 | 1425 | Claude Sonnet 5.5 |
| LMArena Text: medicine and healthcare | 1464 | 1428 | Claude Sonnet 5.5 |
| LMArena Text: legal and government | 1483 | 1418 | Claude Sonnet 5.5 |
| LMArena Text: business and finance | 1468 | 1389 | Claude Sonnet 5.5 |
| FACTS Benchmark Suite | Not measured | 51.4% | Only Gemini 3.1 Flash Lite Preview measured |
| Neither model has a result on the other 5 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index60
| Benchmark | Claude Sonnet 5.5 | Gemini 3.1 Flash Lite Preview | Leader |
|---|---|---|---|
| Design Arena: websites | 1326 | 1082 | Claude Sonnet 5.5 |
| Design Arena: UI components | 1368 | 1069 | Claude Sonnet 5.5 |
| Design Arena: game dev | 1471 | 1029 | Claude Sonnet 5.5 |
| Design Arena: data viz | 1392 | 1045 | Claude Sonnet 5.5 |
| Design Arena: 3D | 1445 | 1047 | Claude Sonnet 5.5 |
| Design Arena: all code categories | 1364 | 1072 | Claude Sonnet 5.5 |
| Design Arena: SVG | Not measured | 1052 | Only Gemini 3.1 Flash Lite Preview measured |
| Design Arena: ASCII art | Not measured | 1167 | Only Gemini 3.1 Flash Lite Preview measured |
| LiveBench design | 85.0% | Not measured | Only Claude Sonnet 5.5 measured |
GeneralLike-for-likePublic boards, shown as published, kept out of the index181
| Benchmark | Claude Sonnet 5.5 | Gemini 3.1 Flash Lite Preview | Leader |
|---|---|---|---|
| Vals Index | 70.8% | Not measured | Only Claude Sonnet 5.5 measured |
| LiveBench data analysis | 59.5% | Not measured | Only Claude Sonnet 5.5 measured |
| Public Benefits Bench (Vals AI) | 67.2% | Not measured | Only Claude Sonnet 5.5 measured |
| SAGE (Vals AI) | 51.8% | 49.5% | Claude Sonnet 5.5 |
| MedScribe (Vals AI) | 91.1% | 63.9% | Claude Sonnet 5.5 |
| Vals Multimodal Index | Not measured | 41.4% | Only Gemini 3.1 Flash Lite Preview measured |
| Long context reasoning (AA-LCR) | 82.7% | Not measured | Only Claude Sonnet 5.5 measured |
| DTBench | 97.3% | Not measured | Only Claude Sonnet 5.5 measured |
| LMCA | 68.3% | Not measured | Only Claude Sonnet 5.5 measured |
| Furniture assembly | 75.0% | Not measured | Only Claude Sonnet 5.5 measured |
| LMArena Text | 1473 | 1416 | Claude Sonnet 5.5 |
| LMArena Text: instruction following | 1492 | 1377 | Claude Sonnet 5.5 |
| LMArena Text: creative writing | 1467 | 1401 | Claude Sonnet 5.5 |
| LMArena Vision | 1287 | 1240 | Claude Sonnet 5.5 |
| LMArena Text: English | 1484 | 1414 | Claude Sonnet 5.5 |
| LMArena Text: non-English | 1456 | 1410 | Claude Sonnet 5.5 |
| LMArena Text: Chinese | 1535 | 1460 | Claude Sonnet 5.5 |
| LMArena Text: German | Not measured | 1430 | Only Gemini 3.1 Flash Lite Preview measured |
| LMArena Text: Japanese | Not measured | 1413 | Only Gemini 3.1 Flash Lite Preview measured |
| LMArena Text: Korean | Not measured | 1392 | Only Gemini 3.1 Flash Lite Preview measured |
| LMArena Text: French | 1499 | 1424 | Claude Sonnet 5.5 |
| LMArena Text: Spanish | 1451 | 1421 | Claude Sonnet 5.5 |
| LMArena Text: Russian | 1454 | 1420 | Claude Sonnet 5.5 |
| LMArena Text: Polish | Not measured | 1443 | Only Gemini 3.1 Flash Lite Preview measured |
| LMArena Text: multi-turn | 1465 | 1417 | Claude Sonnet 5.5 |
| LMArena Text: longer queries | 1495 | 1394 | Claude Sonnet 5.5 |
| LMArena Text: writing and language | 1474 | 1408 | Claude Sonnet 5.5 |
| LMArena Text: entertainment and media | 1461 | 1386 | Claude Sonnet 5.5 |
| LMArena Vision: English | 1289 | 1232 | Claude Sonnet 5.5 |
| LMArena Vision: Chinese | Not measured | 1278 | Only Gemini 3.1 Flash Lite Preview measured |
| LMArena Vision: reading text | 1297 | 1246 | Claude Sonnet 5.5 |
| LMArena Vision: humor | Not measured | 1266 | Only Gemini 3.1 Flash Lite Preview measured |
| LMArena Vision: captioning | Not measured | 1259 | Only Gemini 3.1 Flash Lite Preview measured |
| LMArena Vision: recognizing things | Not measured | 1308 | Only Gemini 3.1 Flash Lite Preview measured |
| LMArena Vision: creative writing | 1242 | 1248 | Gemini 3.1 Flash Lite Preview |
| Neither model has a result on the other 11 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Claude Sonnet 5.5 | Gemini 3.1 Flash Lite Preview | Leader |
|---|---|---|---|
| Neither model has a result on 5 boards here | |||
What each workload costs
Three fixed token mixes at each model's listed price, so per-token rates become a bill.
Chat turn
1K input + 500 output tokens
Gemini 3.1 Flash Lite Preview costs less
Repository review
50K input + 3K output tokens
Gemini 3.1 Flash Lite Preview costs less
Agent loop
200K input + 10K output tokens
Gemini 3.1 Flash Lite Preview costs less
Listed OpenRouter rates, without cache or batch discounts. A workload that does not fit a model's context window would need splitting.
Specification differences
The leading value in a row is marked; a row with a missing value names no leader. Our two rows are marked in red.
| Specification | Anthropic Claude Sonnet 5.5 | Google Gemini 3.1 Flash Lite Preview |
|---|---|---|
| Maker | Anthropic | |
| Weights | No public weights listed | No public weights listed |
| Released | September 28, 2026 | March 3, 2026 |
| Context window | 1M | 1.05M |
| Input $/Mtok | $2.00 | $0.25 |
| Output $/Mtok | $10.00 | $1.50 |
| Coding index | 87.3 | 22.7 |
| Independent measurements behind it | 5 | 3 |
| Cost per solved task | Not computable | $0.18 |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Claude Sonnet 5.5 better than Gemini 3.1 Flash Lite Preview for coding?
Pick Claude Sonnet 5.5 for coding: it scores 87.3 on the Vibe Coding Index against 22.7 for Gemini 3.1 Flash Lite Preview. Pick Gemini 3.1 Flash Lite Preview for output tokens 6.7x cheaper ($1.50 vs $10.00 per million) and a larger context window (1.05M against 1M tokens).
Which is cheaper, Claude Sonnet 5.5 or Gemini 3.1 Flash Lite Preview?
Claude Sonnet 5.5 costs $2.00 per million input tokens and $10.00 per million output tokens; Gemini 3.1 Flash Lite Preview costs $0.25 and $1.50. Cost per solved task is known for Gemini 3.1 Flash Lite Preview only.
Which has the bigger context window, Claude Sonnet 5.5 or Gemini 3.1 Flash Lite Preview?
Gemini 3.1 Flash Lite Preview, with 1.05M tokens against 1M.
How many benchmarks is the Claude Sonnet 5.5 vs Gemini 3.1 Flash Lite Preview comparison based on?
54 benchmarks have a result for both models as of October 22, 2026. Claude Sonnet 5.5's coding index rests on 5 independent benchmarks and Gemini 3.1 Flash Lite Preview's on 3. Where only one model has a result, the page says so instead of naming a winner.