Gemini 2.5 Pro vs Gemini 3.1 Flash Lite Preview

Gemini 3.1 Flash Lite Preview leads Gemini 2.5 Pro on coding, 22.7 to 19.1 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; 59 benchmarks have a result for both.

Replace Gemini 2.5 Pro Replace Gemini 3.1 Flash Lite Preview

Gemini 2.5 ProGoogle

Coding: 19.1
Overall: 41.8
Output $/M: $10.00

Gemini 3.1 Flash Lite PreviewGoogle

Coding: 22.7
Overall: 36.6
Output $/M: $1.50

vs boards won of 59 shared, 1 tied

Gemini 2.5 Pro or Gemini 3.1 Flash Lite Preview: which to pick

Pick Gemini 3.1 Flash Lite Preview for coding: it scores 22.7 on the Vibe Coding Index against 19.1 for Gemini 2.5 Pro.

Pick Gemini 2.5 Pro for work measured by Vibe Code Bench (Vals AI) or LMArena Text: coding, where it leads.

Model AGemini 2.5 ProGoogle19.1/1003 independent benchmarks$0.64 per solved task Model BGemini 3.1 Flash Lite PreviewGoogle22.7/1003 independent benchmarks$0.18 per solved task

593120

Shared results: 59
Gemini 2.5 Pro only: 31
Gemini 3.1 Flash Lite Preview only: 20
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
Gemini 3.1 Flash Lite Preview
Gemini 3.1 Flash Lite Preview scores 22.7 against 19.1.
3 benchmarks behind each score
Intelligence
AA Intelligence Index
Gemini 2.5 Pro
Gemini 2.5 Pro leads, 16.1 against 15.6.
Same board, both measured
Agentic work
AA Agentic Index
No call
Tied at 1.6.
Same board, both measured
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 2.5 Pro
Gemini 2.5 Pro leads, 1167 against 1082.
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 Pro $0.0063, 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 Pro $0.64, Gemini 3.1 Flash Lite Preview $0.18.
Published attempt cost and pass rate

At a glance

Coding index: Gemini 2.5 Pro 19.1 from 3 benchmarks, Gemini 3.1 Flash Lite Preview 22.7 from 3 benchmarks.
Widest category: Web design, 10.9 points apart on average over 6 shared benchmarks.
Widest single gap: Design Arena: data viz: Gemini 2.5 Pro 1222 against Gemini 3.1 Flash Lite Preview 1045, 22.1 points apart on a 0 to 100 scale.
Output price: Gemini 2.5 Pro $10.00 against Gemini 3.1 Flash Lite Preview $1.50 per million output tokens, 6.7x 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.

Boards won, where both have a result
Category	Gemini 2.5 Pro	Gemini 3.1 Flash Lite Preview	Ties
Coding	3	5
Intelligence	1	0
Agentic work	0	0	1 tie
Reasoning	5	0
Math	2	0
Knowledge	9	0
Web design	6	0
General	24	3
All shared boards	50	8	1 tie

CodingLike-for-likeSix of these boards feed the Vibe Coding Index35

Coding benchmarks for Gemini 2.5 Pro and Gemini 3.1 Flash Lite Preview
Benchmark	Gemini 2.5 Pro	Gemini 3.1 Flash Lite Preview	Leader
SWE-bench Verified	53.6%	Not measured	Only Gemini 2.5 Pro measured
LMArena WebDev	1226	1257	Gemini 3.1 Flash Lite Preview
AA Coding Index	33.3	34.7	Gemini 3.1 Flash Lite Preview
LiveCodeBench (Vals AI)	Not measured	80.1%	Only Gemini 3.1 Flash Lite Preview measured
SWE-bench Verified (Vals AI)	54.4%	62.8%	Gemini 3.1 Flash Lite Preview
Vibe Code Bench (Vals AI)	0.4%	0.0%	Gemini 2.5 Pro
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)	80.1%	Not measured	Only Gemini 2.5 Pro measured
SciCode	46.3%	Not measured	Only Gemini 2.5 Pro measured
Terminal-Bench Hard (Artificial Analysis run)	26.5%	Not measured	Only Gemini 2.5 Pro measured
Terminal-Bench	32.6%	Not measured	Only Gemini 2.5 Pro measured
GSO-Bench	3.9%	Not measured	Only Gemini 2.5 Pro measured
WeirdML	54.0%	Not measured	Only Gemini 2.5 Pro measured
ALE-Bench	Not measured	797.7	Only Gemini 3.1 Flash Lite Preview measured
LMArena Text: coding	1452	1400	Gemini 2.5 Pro
LMArena Text: software and IT	1459	1413	Gemini 2.5 Pro
LMArena WebDev: React	Not measured	1245	Only Gemini 3.1 Flash Lite Preview measured
LMArena WebDev: HTML	1235	1276	Gemini 3.1 Flash Lite Preview
LMArena WebDev: from an image	1285	1336	Gemini 3.1 Flash Lite Preview
SciCode	Not measured	4.6%	Only Gemini 3.1 Flash Lite Preview measured
Neither model has a result on the other 17 boards here

IntelligenceLike-for-likePublic boards, shown as published, kept out of the index10

Intelligence benchmarks for Gemini 2.5 Pro and Gemini 3.1 Flash Lite Preview
Benchmark	Gemini 2.5 Pro	Gemini 3.1 Flash Lite Preview	Leader
AA Intelligence Index	16.1	15.6	Gemini 2.5 Pro
Epoch Capabilities Index	145.1	Not measured	Only Gemini 2.5 Pro measured

Agentic workLike-for-likePublic boards, shown as published, kept out of the index00

Agentic work benchmarks for Gemini 2.5 Pro and Gemini 3.1 Flash Lite Preview
Benchmark	Gemini 2.5 Pro	Gemini 3.1 Flash Lite Preview	Leader
AA Agentic Index	1.6	1.6	Tie
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	54.1%	Not measured	Only Gemini 2.5 Pro measured
GDPval	23.3%	Not measured	Only Gemini 2.5 Pro measured
DeepResearch Bench	41.5%	Not measured	Only Gemini 2.5 Pro measured
Vending-Bench 2	$574	Not measured	Only Gemini 2.5 Pro measured
BrowseComp-Plus	29.5%	Not measured	Only Gemini 2.5 Pro measured
Neither model has a result on the other 31 boards here

ReasoningLike-for-likePublic boards, shown as published, kept out of the index50

Reasoning benchmarks for Gemini 2.5 Pro and Gemini 3.1 Flash Lite Preview
Benchmark	Gemini 2.5 Pro	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)	84.4%	Not measured	Only Gemini 2.5 Pro measured
Humanity's Last Exam (Artificial Analysis run)	22.5%	Not measured	Only Gemini 2.5 Pro measured
GPQA Diamond (Epoch AI run)	85.3%	Not measured	Only Gemini 2.5 Pro measured
ARC-AGI	41.0%	Not measured	Only Gemini 2.5 Pro measured
ARC-AGI-2	4.9%	Not measured	Only Gemini 2.5 Pro measured
LMArena Text: hard prompts	1455	1407	Gemini 2.5 Pro
LMArena Text: expert	1452	1398	Gemini 2.5 Pro
LMArena Text: hard prompts in English	1453	1403	Gemini 2.5 Pro
LMArena Vision: diagrams	1274	1242	Gemini 2.5 Pro
LMArena Vision: homework	1281	1271	Gemini 2.5 Pro
Kagi LLM Benchmark	70.3%	Not measured	Only Gemini 2.5 Pro measured
Neither model has a result on the other 9 boards here

MathLike-for-likePublic boards, shown as published, kept out of the index20

Math benchmarks for Gemini 2.5 Pro and Gemini 3.1 Flash Lite Preview
Benchmark	Gemini 2.5 Pro	Gemini 3.1 Flash Lite Preview	Leader
AIME	Not measured	83.3%	Only Gemini 3.1 Flash Lite Preview measured
AA Math Index	87.7	Not measured	Only Gemini 2.5 Pro measured
AIME 2025 (Artificial Analysis run)	87.7%	Not measured	Only Gemini 2.5 Pro measured
OTIS Mock AIME	84.7%	Not measured	Only Gemini 2.5 Pro measured
FrontierMath, tiers 1 to 3	24.6%	Not measured	Only Gemini 2.5 Pro measured
FrontierMath, tier 4	0.0%	Not measured	Only Gemini 2.5 Pro measured
LMArena Text: math	1450	1428	Gemini 2.5 Pro
LMArena Text: mathematical work	1454	1417	Gemini 2.5 Pro
Neither model has a result on the other 5 boards here

KnowledgeLike-for-likePublic boards, shown as published, kept out of the index90

Knowledge benchmarks for Gemini 2.5 Pro and Gemini 3.1 Flash Lite Preview
Benchmark	Gemini 2.5 Pro	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)	63.9%	55.0%	Gemini 2.5 Pro
CorpFin (Vals AI)	60.8%	59.4%	Gemini 2.5 Pro
TaxEval (Vals AI)	Not measured	71.8%	Only Gemini 3.1 Flash Lite Preview measured
MortgageTax (Vals AI)	68.9%	68.0%	Gemini 2.5 Pro
MedCode (Vals AI)	50.6%	47.6%	Gemini 2.5 Pro
MMLU Pro (Artificial Analysis run)	86.2%	Not measured	Only Gemini 2.5 Pro measured
LMArena Text: science	1480	1425	Gemini 2.5 Pro
LMArena Text: medicine and healthcare	1476	1428	Gemini 2.5 Pro
LMArena Text: legal and government	1480	1418	Gemini 2.5 Pro
LMArena Text: business and finance	1439	1389	Gemini 2.5 Pro
FACTS Benchmark Suite	61.5%	51.4%	Gemini 2.5 Pro
Neither model has a result on the other 5 boards here

Web designLike-for-likePublic boards, shown as published, kept out of the index60

Web design benchmarks for Gemini 2.5 Pro and Gemini 3.1 Flash Lite Preview
Benchmark	Gemini 2.5 Pro	Gemini 3.1 Flash Lite Preview	Leader
Design Arena: websites	1167	1082	Gemini 2.5 Pro
Design Arena: UI components	1137	1069	Gemini 2.5 Pro
Design Arena: game dev	1111	1029	Gemini 2.5 Pro
Design Arena: data viz	1222	1045	Gemini 2.5 Pro
Design Arena: 3D	1080	1047	Gemini 2.5 Pro
Design Arena: all code categories	1152	1072	Gemini 2.5 Pro
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
Neither model has a result on the other 1 board here

GeneralLike-for-likePublic boards, shown as published, kept out of the index243

General benchmarks for Gemini 2.5 Pro and Gemini 3.1 Flash Lite Preview
Benchmark	Gemini 2.5 Pro	Gemini 3.1 Flash Lite Preview	Leader
SAGE (Vals AI)	41.9%	49.5%	Gemini 3.1 Flash Lite Preview
MedScribe (Vals AI)	73.5%	63.9%	Gemini 2.5 Pro
Vals Multimodal Index	Not measured	41.4%	Only Gemini 3.1 Flash Lite Preview measured
IFBench	48.7%	Not measured	Only Gemini 2.5 Pro measured
Long context reasoning (AA-LCR)	69.0%	Not measured	Only Gemini 2.5 Pro measured
DTBench	82.4%	Not measured	Only Gemini 2.5 Pro measured
LMCA	34.8%	Not measured	Only Gemini 2.5 Pro measured
Creative writing (Lech Mazur)	83.8%	Not measured	Only Gemini 2.5 Pro measured
LMArena Text	1458	1416	Gemini 2.5 Pro
LMArena Text: instruction following	1437	1377	Gemini 2.5 Pro
LMArena Text: creative writing	1454	1401	Gemini 2.5 Pro
LMArena Vision	1263	1240	Gemini 2.5 Pro
LMArena Text: English	1458	1414	Gemini 2.5 Pro
LMArena Text: non-English	1452	1410	Gemini 2.5 Pro
LMArena Text: Chinese	1507	1460	Gemini 2.5 Pro
LMArena Text: German	1487	1430	Gemini 2.5 Pro
LMArena Text: Japanese	1461	1413	Gemini 2.5 Pro
LMArena Text: Korean	1434	1392	Gemini 2.5 Pro
LMArena Text: French	1473	1424	Gemini 2.5 Pro
LMArena Text: Spanish	1474	1421	Gemini 2.5 Pro
LMArena Text: Russian	1461	1420	Gemini 2.5 Pro
LMArena Text: Polish	1479	1443	Gemini 2.5 Pro
LMArena Text: multi-turn	1453	1417	Gemini 2.5 Pro
LMArena Text: longer queries	1449	1394	Gemini 2.5 Pro
LMArena Text: writing and language	1454	1408	Gemini 2.5 Pro
LMArena Text: entertainment and media	1441	1386	Gemini 2.5 Pro
LMArena Vision: English	1261	1232	Gemini 2.5 Pro
LMArena Vision: Chinese	1300	1278	Gemini 2.5 Pro
LMArena Vision: reading text	1270	1246	Gemini 2.5 Pro
LMArena Vision: humor	1262	1266	Gemini 3.1 Flash Lite Preview
LMArena Vision: captioning	1304	1259	Gemini 2.5 Pro
LMArena Vision: recognizing things	1283	1308	Gemini 3.1 Flash Lite Preview
LMArena Vision: creative writing	1265	1248	Gemini 2.5 Pro
LMArena Document	1421	Not measured	Only Gemini 2.5 Pro measured
Neither model has a result on the other 12 boards here

Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared

Image generation benchmarks for Gemini 2.5 Pro and Gemini 3.1 Flash Lite Preview
Benchmark	Gemini 2.5 Pro	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 2.5 Pro$0.0063Fits in one request

Gemini 3.1 Flash Lite Preview$0.0010Fits in one request

Gemini 3.1 Flash Lite Preview costs less

Repository review

50K input + 3K output tokens

Gemini 2.5 Pro$0.092Fits in one request

Gemini 3.1 Flash Lite Preview$0.017Fits in one request

Gemini 3.1 Flash Lite Preview costs less

Agent loop

200K input + 10K output tokens

Gemini 2.5 Pro$0.350Fits in one request

Gemini 3.1 Flash Lite Preview$0.065Fits in one request

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.

Specifications of Gemini 2.5 Pro and Gemini 3.1 Flash Lite Preview
Specification	Google Gemini 2.5 Pro	Google Gemini 3.1 Flash Lite Preview
Maker	Google	Google
Weights	No public weights listed	No public weights listed
Released	June 17, 2025	March 3, 2026
Context window	1.05M	1.05M
Input $/Mtok	$1.25	$0.25
Output $/Mtok	$10.00	$1.50
Coding index	19.1	22.7
Independent measurements behind it	3	3
Cost per solved task	$0.64	$0.18
Source	OpenRouter listing	OpenRouter listing

Questions

Is Gemini 2.5 Pro better than Gemini 3.1 Flash Lite Preview for coding?

Pick Gemini 3.1 Flash Lite Preview for coding: it scores 22.7 on the Vibe Coding Index against 19.1 for Gemini 2.5 Pro. Pick Gemini 2.5 Pro for work measured by Vibe Code Bench (Vals AI) or LMArena Text: coding, where it leads.

Which is cheaper, Gemini 2.5 Pro or Gemini 3.1 Flash Lite Preview?

Gemini 2.5 Pro costs $1.25 per million input tokens and $10.00 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 Pro costs $0.64 and Gemini 3.1 Flash Lite Preview $0.18.

Which has the bigger context window, Gemini 2.5 Pro or Gemini 3.1 Flash Lite Preview?

Neither: both take 1.05M tokens.

How many benchmarks is the Gemini 2.5 Pro vs Gemini 3.1 Flash Lite Preview comparison based on?

59 benchmarks have a result for both models as of October 22, 2026. Gemini 2.5 Pro's coding index rests on 3 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.

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<p style="font:13px/1.4 sans-serif;margin:6px 0 0">Source: <a href="https://llmbenchmark.ai/compare/gemini-2-5-pro-vs-gemini-3-1-flash-lite-preview">LLMBenchmark.ai, Gemini 2.5 Pro vs Gemini 3.1 Flash Lite Preview</a></p>

Gemini 2.5 Pro or Gemini 3.1 Flash Lite Preview: which to pick

Which one for your work

Coding

Intelligence

Agentic work

Reasoning

Math

Knowledge

Web design

Long documents

Everyday cost

Cost per solved task

At a glance

Benchmark by benchmark

What each workload costs

Chat turn

Repository review

Agent loop

Specification differences

Questions

Compare next