Gemini 2.5 Flash vs Gemini 3.1 Flash Lite Preview
Gemini 3.1 Flash Lite Preview leads Gemini 2.5 Flash on the Artificial Analysis Intelligence Index, 15.6 to 15.5, and Gemini 3.1 Flash Lite Preview costs 1.7x less per output token ($1.50 vs $2.50 per million). Updated October 21, 2026; 50 benchmarks have a result for both.
Gemini 2.5 Flash or Gemini 3.1 Flash Lite Preview: which to pick
Only Gemini 3.1 Flash Lite Preview has a coding score, 22.7 on the Vibe Coding Index; Gemini 2.5 Flash has none, so the two cannot be ranked on coding.
Pick Gemini 2.5 Flash for work measured by LMArena Text: coding or LMArena Text: software and IT, where it leads.
- Shared results
- 50
- Gemini 2.5 Flash only
- 23
- Gemini 3.1 Flash Lite Preview only
- 29
- Like-for-like categories
- 7 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
No call
Only Gemini 3.1 Flash Lite Preview has a coding score, so no call is made.
One side not measured
Intelligence
AA Intelligence Index
Gemini 3.1 Flash Lite Preview
Gemini 3.1 Flash Lite Preview leads, 15.6 against 15.5.
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
Gemini 3.1 Flash Lite Preview
Gemini 3.1 Flash Lite Preview leads, 1083 against 1074.
Same board, both measured
Long documents
Listed context window
No call
Both take 1.05M tokens.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Gemini 3.1 Flash Lite Preview
Gemini 2.5 Flash $0.0015, Gemini 3.1 Flash Lite Preview $0.0010 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
Gemini 3.1 Flash Lite Preview
Gemini 2.5 Flash $0.466, Gemini 3.1 Flash Lite Preview $0.18.
Published attempt cost and pass rate
At a glance
- Coding index
- Gemini 2.5 Flash not benchmarked, Gemini 3.1 Flash Lite Preview 22.7 from 3 benchmarks.
- Widest category
- Web design, 3.3 points apart on average over 7 shared benchmarks.
- Widest single gap
- MedScribe (Vals AI): Gemini 2.5 Flash 83.0% against Gemini 3.1 Flash Lite Preview 63.9%, 19.1 points apart on a 0 to 100 scale.
- Output price
- Gemini 2.5 Flash $2.50 against Gemini 3.1 Flash Lite Preview $1.50 per million output tokens, 1.7x apart.
- Context window
- Both take 1.05M tokens.
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 | Gemini 2.5 Flash | Bars | Gemini 3.1 Flash Lite Preview | Ties |
|---|---|---|---|---|
| Coding | 2 | 0 | ||
| Intelligence | 0 | 1 | ||
| Reasoning | 4 | 1 | ||
| Math | 1 | 1 | ||
| Knowledge | 4 | 2 | ||
| Web design | 1 | 6 | ||
| General | 11 | 16 | ||
| All shared boards | 23 | 27 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index20
| Benchmark | Gemini 2.5 Flash | Gemini 3.1 Flash Lite Preview | Leader |
|---|---|---|---|
| SWE-bench Verified | 28.7% | Not measured | Only Gemini 2.5 Flash measured |
| LMArena WebDev | Not measured | 1257 | Only Gemini 3.1 Flash Lite Preview measured |
| 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 |
| Vibe Code Bench (Vals AI) | Not measured | 0.0% | Only Gemini 3.1 Flash Lite Preview measured |
| Code migration (Vals AI) | Not measured | 4.6% | Only Gemini 3.1 Flash Lite Preview measured |
| ProgramBench (Vals AI) | Not measured | 0.0% | Only Gemini 3.1 Flash Lite Preview measured |
| Terminal-Bench 2.1 (Vals AI) | Not measured | 34.1% | Only Gemini 3.1 Flash Lite Preview measured |
| LiveCodeBench (Artificial Analysis run) | 69.5% | Not measured | Only Gemini 2.5 Flash measured |
| Terminal-Bench Hard (Artificial Analysis run) | 13.6% | Not measured | Only Gemini 2.5 Flash measured |
| Terminal-Bench | 17.1% | Not measured | Only Gemini 2.5 Flash measured |
| ALE-Bench | Not measured | 797.7 | Only Gemini 3.1 Flash Lite Preview measured |
| LMArena Text: coding | 1423 | 1400 | Gemini 2.5 Flash |
| LMArena Text: software and IT | 1425 | 1413 | Gemini 2.5 Flash |
| LMArena WebDev: React | Not measured | 1245 | Only Gemini 3.1 Flash Lite Preview measured |
| LMArena WebDev: HTML | Not measured | 1276 | Only Gemini 3.1 Flash Lite Preview measured |
| LMArena WebDev: from an image | Not measured | 1336 | Only Gemini 3.1 Flash Lite Preview measured |
| SciCode | Not measured | 4.6% | Only Gemini 3.1 Flash Lite Preview measured |
| Neither model has a result on the other 20 boards here | |||
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index01
| Benchmark | Gemini 2.5 Flash | Gemini 3.1 Flash Lite Preview | Leader |
|---|---|---|---|
| AA Intelligence Index | 15.5 | 15.6 | Gemini 3.1 Flash Lite Preview |
| Epoch Capabilities Index | 142.9 | Not measured | Only Gemini 2.5 Flash measured |
Agentic workDirectional onlyPublic boards, shown as published, kept out of the index10 boards, none shared
| Benchmark | Gemini 2.5 Flash | Gemini 3.1 Flash Lite Preview | Leader |
|---|---|---|---|
| AA Agentic Index | Not measured | 1.6 | Only Gemini 3.1 Flash Lite Preview measured |
| Finance Agent (Vals AI) | Not measured | 30.0% | Only Gemini 3.1 Flash Lite Preview measured |
| Tax Agent Bench (Vals AI) | Not measured | 3.1% | Only Gemini 3.1 Flash Lite Preview measured |
| Legal Research Bench (Vals AI) | Not measured | 3.4% | Only Gemini 3.1 Flash Lite Preview measured |
| Excel Modeling Benchmark (Vals AI) | Not measured | 8.6% | Only Gemini 3.1 Flash Lite Preview measured |
| τ²-Bench Telecom | 31.6% | Not measured | Only Gemini 2.5 Flash measured |
| BALROG | 33.5% | Not measured | Only Gemini 2.5 Flash measured |
| Vending-Bench 2 | $549 | Not measured | Only Gemini 2.5 Flash measured |
| Berkeley Function Calling Leaderboard (BFCL) | 56.2% | Not measured | Only Gemini 2.5 Flash measured |
| BrowseComp-Plus | 39.9% | Not measured | Only Gemini 2.5 Flash measured |
| Neither model has a result on the other 31 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index41
| Benchmark | Gemini 2.5 Flash | Gemini 3.1 Flash Lite Preview | Leader |
|---|---|---|---|
| GPQA Diamond | Not measured | 81.1% | Only Gemini 3.1 Flash Lite Preview measured |
| MMMU Pro (Vals AI) | Not measured | 82.5% | Only Gemini 3.1 Flash Lite Preview measured |
| GPQA Diamond (Artificial Analysis run) | 79.0% | Not measured | Only Gemini 2.5 Flash measured |
| Humanity's Last Exam (Artificial Analysis run) | 12.1% | Not measured | Only Gemini 2.5 Flash measured |
| ARC-AGI | 33.3% | Not measured | Only Gemini 2.5 Flash measured |
| ARC-AGI-2 | 2.5% | Not measured | Only Gemini 2.5 Flash measured |
| SimpleBench | 41.2% | Not measured | Only Gemini 2.5 Flash measured |
| LMArena Text: hard prompts | 1422 | 1407 | Gemini 2.5 Flash |
| LMArena Text: expert | 1426 | 1398 | Gemini 2.5 Flash |
| LMArena Text: hard prompts in English | 1420 | 1403 | Gemini 2.5 Flash |
| LMArena Vision: diagrams | 1245 | 1242 | Gemini 2.5 Flash |
| LMArena Vision: homework | 1244 | 1271 | Gemini 3.1 Flash Lite Preview |
| Kagi LLM Benchmark | 56.8% | Not measured | Only Gemini 2.5 Flash measured |
| Neither model has a result on the other 9 boards here | |||
MathLike-for-likePublic boards, shown as published, kept out of the index11
| Benchmark | Gemini 2.5 Flash | Gemini 3.1 Flash Lite Preview | Leader |
|---|---|---|---|
| AIME | Not measured | 83.3% | Only Gemini 3.1 Flash Lite Preview measured |
| AA Math Index | 73.3 | Not measured | Only Gemini 2.5 Flash measured |
| AIME 2025 (Artificial Analysis run) | 73.3% | Not measured | Only Gemini 2.5 Flash measured |
| LMArena Text: math | 1411 | 1428 | Gemini 3.1 Flash Lite Preview |
| LMArena Text: mathematical work | 1422 | 1417 | Gemini 2.5 Flash |
| Neither model has a result on the other 8 boards here | |||
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index42
| Benchmark | Gemini 2.5 Flash | 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) | 40.4% | 47.6% | Gemini 3.1 Flash Lite Preview |
| MMLU Pro (Artificial Analysis run) | 83.2% | Not measured | Only Gemini 2.5 Flash measured |
| LMArena Text: science | 1433 | 1425 | Gemini 2.5 Flash |
| LMArena Text: medicine and healthcare | 1428 | 1428 | Gemini 2.5 Flash |
| LMArena Text: legal and government | 1430 | 1418 | Gemini 2.5 Flash |
| LMArena Text: business and finance | 1404 | 1389 | Gemini 2.5 Flash |
| FACTS Benchmark Suite | 47.2% | 51.4% | Gemini 3.1 Flash Lite Preview |
| Neither model has a result on the other 5 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index16
| Benchmark | Gemini 2.5 Flash | Gemini 3.1 Flash Lite Preview | Leader |
|---|---|---|---|
| Design Arena: websites | 1074 | 1083 | Gemini 3.1 Flash Lite Preview |
| Design Arena: UI components | 1005 | 1072 | Gemini 3.1 Flash Lite Preview |
| Design Arena: game dev | 1005 | 1029 | Gemini 3.1 Flash Lite Preview |
| Design Arena: data viz | 1060 | 1045 | Gemini 2.5 Flash |
| Design Arena: 3D | 1021 | 1048 | Gemini 3.1 Flash Lite Preview |
| Design Arena: all code categories | 1059 | 1072 | Gemini 3.1 Flash Lite Preview |
| Design Arena: SVG | 1020 | 1052 | Gemini 3.1 Flash Lite Preview |
| Design Arena: ASCII art | Not measured | 1167 | Only Gemini 3.1 Flash Lite Preview measured |
| Neither model has a result on the other 1 board here | |||
GeneralLike-for-likePublic boards, shown as published, kept out of the index1116
| Benchmark | Gemini 2.5 Flash | Gemini 3.1 Flash Lite Preview | Leader |
|---|---|---|---|
| SAGE (Vals AI) | 44.8% | 49.5% | Gemini 3.1 Flash Lite Preview |
| MedScribe (Vals AI) | 83.0% | 63.9% | Gemini 2.5 Flash |
| Vals Multimodal Index | Not measured | 41.4% | Only Gemini 3.1 Flash Lite Preview measured |
| IFBench | 50.3% | Not measured | Only Gemini 2.5 Flash measured |
| Long context reasoning (AA-LCR) | 65.3% | Not measured | Only Gemini 2.5 Flash measured |
| DTBench | 76.5% | Not measured | Only Gemini 2.5 Flash measured |
| LMCA | 27.5% | Not measured | Only Gemini 2.5 Flash measured |
| LMArena Text | 1417 | 1416 | Gemini 2.5 Flash |
| LMArena Text: instruction following | 1405 | 1377 | Gemini 2.5 Flash |
| LMArena Text: creative writing | 1400 | 1401 | Gemini 3.1 Flash Lite Preview |
| LMArena Vision | 1235 | 1240 | Gemini 3.1 Flash Lite Preview |
| LMArena Text: English | 1418 | 1414 | Gemini 2.5 Flash |
| LMArena Text: non-English | 1409 | 1410 | Gemini 3.1 Flash Lite Preview |
| LMArena Text: Chinese | 1449 | 1460 | Gemini 3.1 Flash Lite Preview |
| LMArena Text: German | 1417 | 1430 | Gemini 3.1 Flash Lite Preview |
| LMArena Text: Japanese | 1396 | 1413 | Gemini 3.1 Flash Lite Preview |
| LMArena Text: Korean | 1385 | 1392 | Gemini 3.1 Flash Lite Preview |
| LMArena Text: French | 1432 | 1424 | Gemini 2.5 Flash |
| LMArena Text: Spanish | 1422 | 1421 | Gemini 2.5 Flash |
| LMArena Text: Russian | 1415 | 1420 | Gemini 3.1 Flash Lite Preview |
| LMArena Text: Polish | 1413 | 1443 | Gemini 3.1 Flash Lite Preview |
| LMArena Text: multi-turn | 1408 | 1417 | Gemini 3.1 Flash Lite Preview |
| LMArena Text: longer queries | 1419 | 1394 | Gemini 2.5 Flash |
| LMArena Text: writing and language | 1405 | 1408 | Gemini 3.1 Flash Lite Preview |
| LMArena Text: entertainment and media | 1393 | 1386 | Gemini 2.5 Flash |
| LMArena Vision: English | 1239 | 1232 | Gemini 2.5 Flash |
| LMArena Vision: Chinese | 1284 | 1278 | Gemini 2.5 Flash |
| LMArena Vision: reading text | 1237 | 1246 | Gemini 3.1 Flash Lite Preview |
| LMArena Vision: humor | 1225 | 1266 | Gemini 3.1 Flash Lite Preview |
| LMArena Vision: captioning | 1277 | 1259 | Gemini 2.5 Flash |
| LMArena Vision: recognizing things | 1252 | 1308 | Gemini 3.1 Flash Lite Preview |
| LMArena Vision: creative writing | 1241 | 1248 | Gemini 3.1 Flash Lite Preview |
| Neither model has a result on the other 14 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Gemini 2.5 Flash | 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 | Google Gemini 2.5 Flash | Google Gemini 3.1 Flash Lite Preview |
|---|---|---|
| Maker | ||
| Weights | No public weights listed | No public weights listed |
| Released | June 17, 2025 | March 3, 2026 |
| Context window | 1.05M | 1.05M |
| Input $/Mtok | $0.30 | $0.25 |
| Output $/Mtok | $2.50 | $1.50 |
| Coding index | Not benchmarked | 22.7 |
| Independent measurements behind it | 0 | 3 |
| Cost per solved task | $0.466 | $0.18 |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Gemini 2.5 Flash better than Gemini 3.1 Flash Lite Preview for coding?
Only Gemini 3.1 Flash Lite Preview has a coding score, 22.7 on the Vibe Coding Index; Gemini 2.5 Flash has none, so the two cannot be ranked on coding. Pick Gemini 2.5 Flash for work measured by LMArena Text: coding or LMArena Text: software and IT, where it leads.
Which is cheaper, Gemini 2.5 Flash or Gemini 3.1 Flash Lite Preview?
Gemini 2.5 Flash costs $0.30 per million input tokens and $2.50 per million output tokens; Gemini 3.1 Flash Lite Preview costs $0.25 and $1.50. Per solved SWE-bench Verified task, Gemini 2.5 Flash costs $0.466 and Gemini 3.1 Flash Lite Preview $0.18.
Which has the bigger context window, Gemini 2.5 Flash or Gemini 3.1 Flash Lite Preview?
Neither: both take 1.05M tokens.
How many benchmarks is the Gemini 2.5 Flash vs Gemini 3.1 Flash Lite Preview comparison based on?
50 benchmarks have a result for both models as of October 21, 2026. Gemini 2.5 Flash's coding index rests on 0 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.