Gemini 3.1 Pro Preview vs Mistral Medium 3.5

Gemini 3.1 Pro Preview leads Mistral Medium 3.5 on coding, 32.3 to 25.5 on the Vibe Coding Index, and Mistral Medium 3.5 costs 1.6x less per output token ($7.50 vs $12.00 per million). Updated October 22, 2026; 78 benchmarks have a result for both.

Replace Gemini 3.1 Pro Preview Replace Mistral Medium 3.5

Gemini 3.1 Pro PreviewGoogle

Coding: 32.3
Overall: 54.0
Output $/M: $12.00

Mistral Medium 3.5Mistral AI

Coding: 25.5
Overall: 37.3
Output $/M: $7.50

vs boards won of 78 shared

Gemini 3.1 Pro Preview or Mistral Medium 3.5: which to pick

Pick Gemini 3.1 Pro Preview for coding: it scores 32.3 on the Vibe Coding Index against 25.5 for Mistral Medium 3.5.

Pick Mistral Medium 3.5 for output tokens 1.6x cheaper ($7.50 vs $12.00 per million).

Model AGemini 3.1 Pro PreviewGoogle32.3/1004 independent benchmarks$0.99 per solved task Model BMistral Medium 3.5Mistral AI25.5/1003 independent benchmarks$6.02 per solved task

78553

Shared results: 78
Gemini 3.1 Pro Preview only: 55
Mistral Medium 3.5 only: 3
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 Pro Preview
Gemini 3.1 Pro Preview scores 32.3 against 25.5.
4 and 3 benchmarks behind the scores
Intelligence
AA Intelligence Index
Gemini 3.1 Pro Preview
Gemini 3.1 Pro Preview leads, 29.7 against 14.2.
Same board, both measured
Agentic work
AA Agentic Index
Gemini 3.1 Pro Preview
Gemini 3.1 Pro Preview leads, 8.2 against 7.0.
Same board, both measured
Reasoning
GPQA Diamond
Gemini 3.1 Pro Preview
Gemini 3.1 Pro Preview leads, 95.5% against 34.9%.
Same board, both measured
Math
AIME
No call
Only Gemini 3.1 Pro Preview has a AIME result, 98.1%.
Directional only
Knowledge
MMLU Pro
Gemini 3.1 Pro Preview
Gemini 3.1 Pro Preview leads, 91.0% against 75.3%.
Same board, both measured
Web design
Design Arena: websites
Gemini 3.1 Pro Preview
Gemini 3.1 Pro Preview leads, 1233 against 1142.
Same board, both measured
Long documents
Listed context window
Gemini 3.1 Pro Preview
Gemini 3.1 Pro Preview takes 1.05M tokens against 262K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Mistral Medium 3.5
Gemini 3.1 Pro Preview $0.0080, Mistral Medium 3.5 $0.0053 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
Gemini 3.1 Pro Preview
Gemini 3.1 Pro Preview $0.99, Mistral Medium 3.5 $6.02.
Published attempt cost and pass rate

At a glance

Coding index: Gemini 3.1 Pro Preview 32.3 from 4 benchmarks, Mistral Medium 3.5 25.5 from 3 benchmarks.
Widest category: Web design, 20.0 points apart on average over 8 shared benchmarks.
Widest single gap: GPQA Diamond: Gemini 3.1 Pro Preview 95.5% against Mistral Medium 3.5 34.9%, 60.6 points apart on a 0 to 100 scale.
Output price: Gemini 3.1 Pro Preview $12.00 against Mistral Medium 3.5 $7.50 per million output tokens, 1.6x apart.
Context window: Gemini 3.1 Pro Preview takes 1.05M tokens, Mistral Medium 3.5 262K.

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 3.1 Pro Preview	Bars	Mistral Medium 3.5	Ties
Coding	13		0
Intelligence	1		0
Agentic work	6		0
Reasoning	8		0
Math	3		0
Knowledge	10		0
Web design	8		0
General	29		0
All shared boards	78		0

CodingLike-for-likeSix of these boards feed the Vibe Coding Index130

Coding benchmarks for Gemini 3.1 Pro Preview and Mistral Medium 3.5
Benchmark	Gemini 3.1 Pro Preview	Mistral Medium 3.5	Leader
LMArena WebDev	1447	1264	Gemini 3.1 Pro Preview
AA Coding Index	68.8	46.9	Gemini 3.1 Pro Preview
LiveCodeBench (Vals AI)	88.5%	Not measured	Only Gemini 3.1 Pro Preview measured
SWE-bench Verified (Vals AI)	78.8%	66.4%	Gemini 3.1 Pro Preview
Terminal-Bench 4 (Vals AI)	2.5%	Not measured	Only Gemini 3.1 Pro Preview measured
Vibe Code Bench (Vals AI)	32.0%	2.9%	Gemini 3.1 Pro Preview
Code migration (Vals AI)	17.3%	5.1%	Gemini 3.1 Pro Preview
ProgramBench (Vals AI)	0.0%	Not measured	Only Gemini 3.1 Pro Preview measured
IOI (Vals AI)	51.8%	Not measured	Only Gemini 3.1 Pro Preview measured
Terminal-Bench 2.1 (Vals AI)	70.8%	39.0%	Gemini 3.1 Pro Preview
Vibe Code Bench 1-100 (Vals AI)	6.7%	Not measured	Only Gemini 3.1 Pro Preview measured
SciCode	58.7%	40.2%	Gemini 3.1 Pro Preview
Terminal-Bench Hard (Artificial Analysis run)	53.8%	33.3%	Gemini 3.1 Pro Preview
Terminal-Bench	80.2%	Not measured	Only Gemini 3.1 Pro Preview measured
GSO-Bench	22.6%	Not measured	Only Gemini 3.1 Pro Preview measured
WeirdML	72.1%	Not measured	Only Gemini 3.1 Pro Preview measured
MirrorCode	8.9%	Not measured	Only Gemini 3.1 Pro Preview measured
ALE-Bench	1160.6	764.0	Gemini 3.1 Pro Preview
LMArena Text: coding	1484	1460	Gemini 3.1 Pro Preview
LMArena Text: software and IT	1487	1458	Gemini 3.1 Pro Preview
LMArena WebDev: React	1438	1254	Gemini 3.1 Pro Preview
LMArena WebDev: HTML	1490	1308	Gemini 3.1 Pro Preview
LMArena WebDev: from an image	1481	Not measured	Only Gemini 3.1 Pro Preview measured
SciCode	14.3%	Not measured	Only Gemini 3.1 Pro Preview measured
Neither model has a result on the other 15 boards here

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

Intelligence benchmarks for Gemini 3.1 Pro Preview and Mistral Medium 3.5
Benchmark	Gemini 3.1 Pro Preview	Mistral Medium 3.5	Leader
AA Intelligence Index	29.7	14.2	Gemini 3.1 Pro Preview
Epoch Capabilities Index	Not measured	141.4	Only Mistral Medium 3.5 measured

Agentic workLike-for-likePublic boards, shown as published, kept out of the index60

Agentic work benchmarks for Gemini 3.1 Pro Preview and Mistral Medium 3.5
Benchmark	Gemini 3.1 Pro Preview	Mistral Medium 3.5	Leader
AA Agentic Index	8.2	7.0	Gemini 3.1 Pro Preview
Design Arena: agents building web apps	1125	Not measured	Only Gemini 3.1 Pro Preview measured
Design Arena: agents building full-stack apps	1068	Not measured	Only Gemini 3.1 Pro Preview measured
Design Arena: agents building mobile apps	1094	Not measured	Only Gemini 3.1 Pro Preview measured
Design Arena: agents building Android apps	1049	Not measured	Only Gemini 3.1 Pro Preview measured
Design Arena: agents building Godot games	1236	Not measured	Only Gemini 3.1 Pro Preview measured
Design Arena: agents building games	1113	Not measured	Only Gemini 3.1 Pro Preview measured
Design Arena: HTML slides	1103	Not measured	Only Gemini 3.1 Pro Preview measured
Design Arena: PowerPoint slides	1041	Not measured	Only Gemini 3.1 Pro Preview measured
SREBench (Vals AI)	0.0%	Not measured	Only Gemini 3.1 Pro Preview measured
Finance Agent (Vals AI)	43.0%	32.1%	Gemini 3.1 Pro Preview
Tax Agent Bench (Vals AI)	9.3%	4.5%	Gemini 3.1 Pro Preview
Legal Research Bench (Vals AI)	20.7%	9.1%	Gemini 3.1 Pro Preview
Excel Modeling Benchmark (Vals AI)	52.6%	11.2%	Gemini 3.1 Pro Preview
BioMysteryBench (Vals AI)	60.0%	Not measured	Only Gemini 3.1 Pro Preview measured
Terminal-Bench-Science (Vals AI)	1.4%	Not measured	Only Gemini 3.1 Pro Preview measured
Vals Science Index	27.4%	Not measured	Only Gemini 3.1 Pro Preview measured
τ²-Bench Telecom	95.6%	94.2%	Gemini 3.1 Pro Preview
APEX-Agents	35.1%	Not measured	Only Gemini 3.1 Pro Preview measured
METR time horizons	77.0%	Not measured	Only Gemini 3.1 Pro Preview measured
BALROG	57.0%	Not measured	Only Gemini 3.1 Pro Preview measured
DeepResearch Bench	47.8%	Not measured	Only Gemini 3.1 Pro Preview measured
PostTrainBench	22.0%	Not measured	Only Gemini 3.1 Pro Preview measured
Vending-Bench 2	$911	Not measured	Only Gemini 3.1 Pro Preview measured
Neither model has a result on the other 17 boards here

ReasoningLike-for-likePublic boards, shown as published, kept out of the index80

Reasoning benchmarks for Gemini 3.1 Pro Preview and Mistral Medium 3.5
Benchmark	Gemini 3.1 Pro Preview	Mistral Medium 3.5	Leader
GPQA Diamond	95.5%	34.9%	Gemini 3.1 Pro Preview
MysteryMechanism (Vals AI)	20.7%	Not measured	Only Gemini 3.1 Pro Preview measured
MMMU Pro (Vals AI)	88.2%	Not measured	Only Gemini 3.1 Pro Preview measured
GPQA Diamond (Artificial Analysis run)	94.1%	74.8%	Gemini 3.1 Pro Preview
Humanity's Last Exam (Artificial Analysis run)	47.0%	13.8%	Gemini 3.1 Pro Preview
GPQA Diamond (Epoch AI run)	94.4%	Not measured	Only Gemini 3.1 Pro Preview measured
ARC-AGI	98.0%	Not measured	Only Gemini 3.1 Pro Preview measured
ARC-AGI-2	77.1%	Not measured	Only Gemini 3.1 Pro Preview measured
SimpleBench	79.6%	Not measured	Only Gemini 3.1 Pro Preview measured
Chess puzzles	51.0%	Not measured	Only Gemini 3.1 Pro Preview measured
Mystery game puzzles	34.0%	Not measured	Only Gemini 3.1 Pro Preview measured
EBR-bench	14.3%	Not measured	Only Gemini 3.1 Pro Preview measured
LMArena Text: hard prompts	1485	1436	Gemini 3.1 Pro Preview
LMArena Text: expert	1483	1432	Gemini 3.1 Pro Preview
LMArena Text: hard prompts in English	1480	1445	Gemini 3.1 Pro Preview
LMArena Vision: diagrams	1311	1254	Gemini 3.1 Pro Preview
LMArena Vision: homework	1316	1230	Gemini 3.1 Pro Preview
Kagi LLM Benchmark	Not measured	41.4%	Only Mistral Medium 3.5 measured
Neither model has a result on the other 4 boards here

MathLike-for-likePublic boards, shown as published, kept out of the index30

Math benchmarks for Gemini 3.1 Pro Preview and Mistral Medium 3.5
Benchmark	Gemini 3.1 Pro Preview	Mistral Medium 3.5	Leader
AIME	98.1%	Not measured	Only Gemini 3.1 Pro Preview measured
OTIS Mock AIME	95.6%	Not measured	Only Gemini 3.1 Pro Preview measured
FrontierMath, tiers 1 to 3	59.6%	Not measured	Only Gemini 3.1 Pro Preview measured
FrontierMath, tier 4	26.8%	Not measured	Only Gemini 3.1 Pro Preview measured
ProofBench	26.0%	9.0%	Gemini 3.1 Pro Preview
LMArena Text: math	1486	1431	Gemini 3.1 Pro Preview
LMArena Text: mathematical work	1478	1440	Gemini 3.1 Pro Preview
Neither model has a result on the other 6 boards here

KnowledgeLike-for-likePublic boards, shown as published, kept out of the index100

Knowledge benchmarks for Gemini 3.1 Pro Preview and Mistral Medium 3.5
Benchmark	Gemini 3.1 Pro Preview	Mistral Medium 3.5	Leader
MMLU Pro	91.0%	75.3%	Gemini 3.1 Pro Preview
LegalBench (Vals AI)	87.4%	Not measured	Only Gemini 3.1 Pro Preview measured
CaseLaw (Vals AI)	64.8%	44.2%	Gemini 3.1 Pro Preview
CorpFin (Vals AI)	64.5%	58.8%	Gemini 3.1 Pro Preview
TaxEval (Vals AI)	72.9%	68.0%	Gemini 3.1 Pro Preview
MortgageTax (Vals AI)	69.4%	28.9%	Gemini 3.1 Pro Preview
MedQA (Vals AI)	96.4%	Not measured	Only Gemini 3.1 Pro Preview measured
MedCode (Vals AI)	59.1%	33.8%	Gemini 3.1 Pro Preview
SimpleQA Verified	73.5%	Not measured	Only Gemini 3.1 Pro Preview measured
LMArena Text: science	1497	1428	Gemini 3.1 Pro Preview
LMArena Text: medicine and healthcare	1486	1409	Gemini 3.1 Pro Preview
LMArena Text: legal and government	1487	1437	Gemini 3.1 Pro Preview
LMArena Text: business and finance	1459	1426	Gemini 3.1 Pro Preview
FACTS Benchmark Suite	67.4%	Not measured	Only Gemini 3.1 Pro Preview measured
Neither model has a result on the other 4 boards here

Web designLike-for-likePublic boards, shown as published, kept out of the index80

Web design benchmarks for Gemini 3.1 Pro Preview and Mistral Medium 3.5
Benchmark	Gemini 3.1 Pro Preview	Mistral Medium 3.5	Leader
Design Arena: websites	1233	1142	Gemini 3.1 Pro Preview
Design Arena: UI components	1224	1076	Gemini 3.1 Pro Preview
Design Arena: game dev	1202	1079	Gemini 3.1 Pro Preview
Design Arena: data viz	1209	1120	Gemini 3.1 Pro Preview
Design Arena: 3D	1234	1060	Gemini 3.1 Pro Preview
Design Arena: all code categories	1231	1121	Gemini 3.1 Pro Preview
Design Arena: SVG	1285	949	Gemini 3.1 Pro Preview
Design Arena: ASCII art	1270	1062	Gemini 3.1 Pro Preview
Neither model has a result on the other 1 board here

GeneralLike-for-likePublic boards, shown as published, kept out of the index290

General benchmarks for Gemini 3.1 Pro Preview and Mistral Medium 3.5
Benchmark	Gemini 3.1 Pro Preview	Mistral Medium 3.5	Leader
Public Benefits Bench (Vals AI)	53.8%	Not measured	Only Gemini 3.1 Pro Preview measured
SAGE (Vals AI)	48.7%	37.6%	Gemini 3.1 Pro Preview
MedScribe (Vals AI)	76.1%	67.7%	Gemini 3.1 Pro Preview
Vals Multimodal Index	56.1%	34.8%	Gemini 3.1 Pro Preview
IFBench	77.1%	68.8%	Gemini 3.1 Pro Preview
Long context reasoning (AA-LCR)	82.0%	69.3%	Gemini 3.1 Pro Preview
DTBench	97.1%	75.5%	Gemini 3.1 Pro Preview
LMCA	53.8%	26.1%	Gemini 3.1 Pro Preview
CL-bench	20.8%	Not measured	Only Gemini 3.1 Pro Preview measured
Surface Evolver Bench	Not measured	26.9%	Only Mistral Medium 3.5 measured
Furniture assembly	26.7%	Not measured	Only Gemini 3.1 Pro Preview measured
ExploitBench	26.1%	Not measured	Only Gemini 3.1 Pro Preview measured
CL-bench Life	16.9%	Not measured	Only Gemini 3.1 Pro Preview measured
LMArena Text	1480	1421	Gemini 3.1 Pro Preview
LMArena Text: instruction following	1466	1415	Gemini 3.1 Pro Preview
LMArena Text: creative writing	1482	1374	Gemini 3.1 Pro Preview
LMArena Vision	1296	1222	Gemini 3.1 Pro Preview
LMArena Text: English	1478	1433	Gemini 3.1 Pro Preview
LMArena Text: non-English	1476	1404	Gemini 3.1 Pro Preview
LMArena Text: Chinese	1527	1444	Gemini 3.1 Pro Preview
LMArena Text: German	1490	1453	Gemini 3.1 Pro Preview
LMArena Text: Japanese	1491	Not measured	Only Gemini 3.1 Pro Preview measured
LMArena Text: Korean	1455	1384	Gemini 3.1 Pro Preview
LMArena Text: French	1487	1448	Gemini 3.1 Pro Preview
LMArena Text: Spanish	1481	1411	Gemini 3.1 Pro Preview
LMArena Text: Russian	1497	1395	Gemini 3.1 Pro Preview
LMArena Text: Polish	1498	1430	Gemini 3.1 Pro Preview
LMArena Text: multi-turn	1487	1423	Gemini 3.1 Pro Preview
LMArena Text: longer queries	1482	1415	Gemini 3.1 Pro Preview
LMArena Text: writing and language	1481	1384	Gemini 3.1 Pro Preview
LMArena Text: entertainment and media	1465	1382	Gemini 3.1 Pro Preview
LMArena Vision: English	1287	1240	Gemini 3.1 Pro Preview
LMArena Vision: Chinese	1364	1244	Gemini 3.1 Pro Preview
LMArena Vision: reading text	1304	1233	Gemini 3.1 Pro Preview
LMArena Vision: humor	1322	1216	Gemini 3.1 Pro Preview
LMArena Vision: captioning	1345	Not measured	Only Gemini 3.1 Pro Preview measured
LMArena Vision: recognizing things	1330	Not measured	Only Gemini 3.1 Pro Preview measured
LMArena Vision: creative writing	1324	1198	Gemini 3.1 Pro Preview
LMArena Document	1444	Not measured	Only Gemini 3.1 Pro Preview measured
Neither model has a result on the other 7 boards here

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

Image generation benchmarks for Gemini 3.1 Pro Preview and Mistral Medium 3.5
Benchmark	Gemini 3.1 Pro Preview	Mistral Medium 3.5	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 Pro Preview$0.0080Fits in one request

Mistral Medium 3.5$0.0053Fits in one request

Mistral Medium 3.5 costs less

Repository review

50K input + 3K output tokens

Gemini 3.1 Pro Preview$0.136Fits in one request

Mistral Medium 3.5$0.098Fits in one request

Mistral Medium 3.5 costs less

Agent loop

200K input + 10K output tokens

Gemini 3.1 Pro Preview$0.520Fits in one request

Mistral Medium 3.5$0.375Fits in one request

Mistral Medium 3.5 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 3.1 Pro Preview and Mistral Medium 3.5
Specification	Google Gemini 3.1 Pro Preview	Mistral Medium 3.5
Maker	Google	Mistral AI
Weights	No public weights listed	No public weights listed
Released	February 19, 2026	April 30, 2026
Context window	1.05M	262K
Input $/Mtok	$2.00	$1.50
Output $/Mtok	$12.00	$7.50
Coding index	32.3	25.5
Independent measurements behind it	4	3
Cost per solved task	$0.99	$6.02
Source	OpenRouter listing	OpenRouter listing

Questions

Is Gemini 3.1 Pro Preview better than Mistral Medium 3.5 for coding?

Pick Gemini 3.1 Pro Preview for coding: it scores 32.3 on the Vibe Coding Index against 25.5 for Mistral Medium 3.5. Pick Mistral Medium 3.5 for output tokens 1.6x cheaper ($7.50 vs $12.00 per million).

Which is cheaper, Gemini 3.1 Pro Preview or Mistral Medium 3.5?

Gemini 3.1 Pro Preview costs $2.00 per million input tokens and $12.00 per million output tokens; Mistral Medium 3.5 costs $1.50 and $7.50. Per solved SWE-bench Verified task, Gemini 3.1 Pro Preview costs $0.99 and Mistral Medium 3.5 $6.02.

Which has the bigger context window, Gemini 3.1 Pro Preview or Mistral Medium 3.5?

Gemini 3.1 Pro Preview, with 1.05M tokens against 262K.

How many benchmarks is the Gemini 3.1 Pro Preview vs Mistral Medium 3.5 comparison based on?

78 benchmarks have a result for both models as of October 22, 2026. Gemini 3.1 Pro Preview's coding index rests on 4 independent benchmarks and Mistral Medium 3.5's on 3. Where only one model has a result, the page says so instead of naming a winner.

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Gemini 3.1 Pro Preview or Mistral Medium 3.5: 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