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Kimi K3 vs Mistral Medium 3.5

Kimi K3 leads Mistral Medium 3.5 on coding, 62.3 to 25.5 on the Vibe Coding Index, and Mistral Medium 3.5 costs 2.0x less per output token ($7.50 vs $15.00 per million). Updated October 21, 2026; 67 benchmarks have a result for both.

Replace Kimi K3 Replace Mistral Medium 3.5
Kimi K3Moonshot AI
Coding
62.3
Overall
66.5
Output $/M
$15.00
67
Mistral Medium 3.5Mistral AI
Coding
25.5
Overall
37.3
Output $/M
$7.50
0
vs boards won of 67 shared

Kimi K3 or Mistral Medium 3.5: which to pick

Pick Kimi K3 for coding: it scores 62.3 on the Vibe Coding Index against 25.5 for Mistral Medium 3.5.

Pick Mistral Medium 3.5 for output tokens 2.0x cheaper ($7.50 vs $15.00 per million).

Model AKimi K3Moonshot AI62.3/1006 independent benchmarks$0.81 per solved taskModel BMistral Medium 3.5Mistral AI25.5/1003 independent benchmarks$6.02 per solved task
Shared results
67
Kimi K3 only
50
Mistral Medium 3.5 only
14
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.

At a glance

Coding index
Kimi K3 62.3 from 6 benchmarks, Mistral Medium 3.5 25.5 from 3 benchmarks.
Widest category
Agentic work, 37.1 points apart on average over 5 shared benchmarks.
Widest single gap
Vibe Code Bench (Vals AI): Kimi K3 85.0% against Mistral Medium 3.5 2.9%, 82.1 points apart on a 0 to 100 scale.
Output price
Kimi K3 $15.00 against Mistral Medium 3.5 $7.50 per million output tokens, 2.0x apart.
Context window
Kimi K3 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
CategoryKimi K3BarsMistral Medium 3.5Ties
Coding120
Intelligence20
Agentic work50
Reasoning60
Math30
Knowledge90
Web design70
General230
All shared boards670
CodingLike-for-likeSix of these boards feed the Vibe Coding Index120
Coding benchmarks for Kimi K3 and Mistral Medium 3.5
BenchmarkKimi K3Mistral Medium 3.5Leader
LiveBench coding59.3%Not measuredOnly Kimi K3 measured
LMArena WebDev16551264Kimi K3
AA Coding Index76.246.9Kimi K3
LiveCodeBench (Vals AI)87.2%Not measuredOnly Kimi K3 measured
SWE-bench Verified (Vals AI)93.4%66.4%Kimi K3
Terminal-Bench 4 (Vals AI)17.2%Not measuredOnly Kimi K3 measured
Vibe Code Bench (Vals AI)85.0%2.9%Kimi K3
Code migration (Vals AI)16.1%5.1%Kimi K3
ProgramBench (Vals AI)2.0%Not measuredOnly Kimi K3 measured
IOI (Vals AI)48.9%Not measuredOnly Kimi K3 measured
Terminal-Bench 2.1 (Vals AI)80.9%39.0%Kimi K3
SWE-bench Multimodal (Vals AI)44.2%Not measuredOnly Kimi K3 measured
Vibe Code Bench 1-100 (Vals AI)18.2%Not measuredOnly Kimi K3 measured
CyberBench (Vals AI)75.2%Not measuredOnly Kimi K3 measured
SciCode59.5%40.2%Kimi K3
Terminal-Bench Hard (Artificial Analysis run)Not measured33.3%Only Mistral Medium 3.5 measured
FrontierCode44.2%Not measuredOnly Kimi K3 measured
FrontierSWE25.9%Not measuredOnly Kimi K3 measured
WeirdML82.6%Not measuredOnly Kimi K3 measured
ALE-Bench1524.5764.0Kimi K3
LMArena Text: coding15081460Kimi K3
LMArena Text: software and IT14991458Kimi K3
LMArena WebDev: React16701254Kimi K3
LMArena WebDev: HTML16441308Kimi K3
LMArena WebDev: from an image1579Not measuredOnly Kimi K3 measured
Neither model has a result on the other 14 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index20
Intelligence benchmarks for Kimi K3 and Mistral Medium 3.5
BenchmarkKimi K3Mistral Medium 3.5Leader
AA Intelligence Index43.614.2Kimi K3
Epoch Capabilities Index157.9141.4Kimi K3
Agentic workLike-for-likePublic boards, shown as published, kept out of the index50
Agentic work benchmarks for Kimi K3 and Mistral Medium 3.5
BenchmarkKimi K3Mistral Medium 3.5Leader
AA Agentic Index50.07.0Kimi K3
Design Arena: agents building web apps1295Not measuredOnly Kimi K3 measured
Design Arena: agents building full-stack apps1315Not measuredOnly Kimi K3 measured
Design Arena: agents building mobile apps1269Not measuredOnly Kimi K3 measured
Design Arena: agents building Android apps1250Not measuredOnly Kimi K3 measured
Design Arena: agents building Godot games1223Not measuredOnly Kimi K3 measured
Design Arena: agents building games1252Not measuredOnly Kimi K3 measured
Design Arena: HTML slides1256Not measuredOnly Kimi K3 measured
Design Arena: PowerPoint slides1273Not measuredOnly Kimi K3 measured
Design Arena: spreadsheets1058Not measuredOnly Kimi K3 measured
LiveBench research79.0%Not measuredOnly Kimi K3 measured
LiveBench browser16.0%Not measuredOnly Kimi K3 measured
LiveBench long agentic42.8%Not measuredOnly Kimi K3 measured
Finance Agent (Vals AI)53.1%32.1%Kimi K3
Tax Agent Bench (Vals AI)33.4%4.5%Kimi K3
Legal Research Bench (Vals AI)46.1%9.1%Kimi K3
Harvey's Legal Agent Benchmark (Vals AI)12.9%Not measuredOnly Kimi K3 measured
Excel Modeling Benchmark (Vals AI)66.7%11.2%Kimi K3
BioMysteryBench (Vals AI)72.6%Not measuredOnly Kimi K3 measured
Terminal-Bench-Science (Vals AI)1.4%Not measuredOnly Kimi K3 measured
Time Horizon Index (Vals AI)10.5%Not measuredOnly Kimi K3 measured
τ²-Bench TelecomNot measured94.2%Only Mistral Medium 3.5 measured
APEX-Agents47.8%Not measuredOnly Kimi K3 measured
PostTrainBench32.0%Not measuredOnly Kimi K3 measured
Vending-Bench 2$5,165Not measuredOnly Kimi K3 measured
Neither model has a result on the other 16 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index60
Reasoning benchmarks for Kimi K3 and Mistral Medium 3.5
BenchmarkKimi K3Mistral Medium 3.5Leader
GPQA Diamond92.9%34.9%Kimi K3
LiveBench reasoning90.7%Not measuredOnly Kimi K3 measured
MMMU Pro (Vals AI)88.2%Not measuredOnly Kimi K3 measured
GPQA Diamond (Artificial Analysis run)93.5%74.8%Kimi K3
Humanity's Last Exam (Artificial Analysis run)46.9%13.8%Kimi K3
GPQA Diamond (Epoch AI run)93.1%Not measuredOnly Kimi K3 measured
ARC-AGI94.5%Not measuredOnly Kimi K3 measured
ARC-AGI-260.4%Not measuredOnly Kimi K3 measured
SimpleBench60.7%Not measuredOnly Kimi K3 measured
Chess puzzles37.0%Not measuredOnly Kimi K3 measured
Mystery game puzzles26.0%Not measuredOnly Kimi K3 measured
LMArena Text: hard prompts14951436Kimi K3
LMArena Text: expert15201432Kimi K3
LMArena Text: hard prompts in English14961445Kimi K3
LMArena Vision: diagramsNot measured1254Only Mistral Medium 3.5 measured
LMArena Vision: homeworkNot measured1230Only Mistral Medium 3.5 measured
Kagi LLM BenchmarkNot measured41.4%Only Mistral Medium 3.5 measured
Neither model has a result on the other 5 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index30
Math benchmarks for Kimi K3 and Mistral Medium 3.5
BenchmarkKimi K3Mistral Medium 3.5Leader
OTIS Mock AIME97.2%Not measuredOnly Kimi K3 measured
FrontierMath, tiers 1 to 372.2%Not measuredOnly Kimi K3 measured
FrontierMath, tier 439.0%Not measuredOnly Kimi K3 measured
ProofBench87.0%9.0%Kimi K3
LMArena Text: math14941431Kimi K3
LMArena Text: mathematical work15051440Kimi K3
Neither model has a result on the other 7 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index90
Knowledge benchmarks for Kimi K3 and Mistral Medium 3.5
BenchmarkKimi K3Mistral Medium 3.5Leader
MMLU Pro88.0%75.3%Kimi K3
LegalBench (Vals AI)86.2%Not measuredOnly Kimi K3 measured
CaseLaw (Vals AI)Not measured44.2%Only Mistral Medium 3.5 measured
CorpFin (Vals AI)71.6%58.8%Kimi K3
TaxEval (Vals AI)75.7%68.0%Kimi K3
MortgageTax (Vals AI)66.3%28.9%Kimi K3
MedCode (Vals AI)49.4%33.8%Kimi K3
SimpleQA Verified50.6%Not measuredOnly Kimi K3 measured
LMArena Text: science15081428Kimi K3
LMArena Text: medicine and healthcare14891409Kimi K3
LMArena Text: legal and government15031437Kimi K3
LMArena Text: business and finance14701426Kimi K3
Neither model has a result on the other 6 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index70
Web design benchmarks for Kimi K3 and Mistral Medium 3.5
BenchmarkKimi K3Mistral Medium 3.5Leader
Design Arena: websites13351142Kimi K3
Design Arena: UI components13441079Kimi K3
Design Arena: game dev13591079Kimi K3
Design Arena: data viz13511120Kimi K3
Design Arena: 3D13881061Kimi K3
Design Arena: all code categories13601121Kimi K3
Design Arena: SVG1302950Kimi K3
Design Arena: ASCII artNot measured1063Only Mistral Medium 3.5 measured
LiveBench design77.2%Not measuredOnly Kimi K3 measured
GeneralLike-for-likePublic boards, shown as published, kept out of the index230
General benchmarks for Kimi K3 and Mistral Medium 3.5
BenchmarkKimi K3Mistral Medium 3.5Leader
Vals Index53.0%Not measuredOnly Kimi K3 measured
LiveBench data analysis78.7%Not measuredOnly Kimi K3 measured
Public Benefits Bench (Vals AI)68.2%Not measuredOnly Kimi K3 measured
SAGE (Vals AI)52.8%37.6%Kimi K3
MedScribe (Vals AI)88.0%67.7%Kimi K3
Vals Multimodal Index73.4%34.8%Kimi K3
IFBenchNot measured68.8%Only Mistral Medium 3.5 measured
Long context reasoning (AA-LCR)88.7%69.3%Kimi K3
DTBench91.2%75.5%Kimi K3
LMCA52.7%26.1%Kimi K3
Surface Evolver Bench95.0%26.9%Kimi K3
Furniture assembly34.2%Not measuredOnly Kimi K3 measured
LMArena Text14761421Kimi K3
LMArena Text: instruction following14851415Kimi K3
LMArena Text: creative writing14571374Kimi K3
LMArena VisionNot measured1222Only Mistral Medium 3.5 measured
LMArena Text: English14811433Kimi K3
LMArena Text: non-English14661404Kimi K3
LMArena Text: Chinese15291444Kimi K3
LMArena Text: German14901453Kimi K3
LMArena Text: Japanese1494Not measuredOnly Kimi K3 measured
LMArena Text: Korean14601384Kimi K3
LMArena Text: French14921448Kimi K3
LMArena Text: Spanish14721411Kimi K3
LMArena Text: Russian14851395Kimi K3
LMArena Text: Polish14581430Kimi K3
LMArena Text: multi-turn14891423Kimi K3
LMArena Text: longer queries14941415Kimi K3
LMArena Text: writing and language14711384Kimi K3
LMArena Text: entertainment and media14531382Kimi K3
LMArena Vision: EnglishNot measured1240Only Mistral Medium 3.5 measured
LMArena Vision: ChineseNot measured1244Only Mistral Medium 3.5 measured
LMArena Vision: reading textNot measured1233Only Mistral Medium 3.5 measured
LMArena Vision: humorNot measured1216Only Mistral Medium 3.5 measured
LMArena Vision: creative writingNot measured1198Only Mistral Medium 3.5 measured
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
Image generation benchmarks for Kimi K3 and Mistral Medium 3.5
BenchmarkKimi K3Mistral Medium 3.5Leader
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

Kimi K3$0.011Fits 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

Kimi K3$0.195Fits 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

Kimi K3$0.750Fits 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 Kimi K3 and Mistral Medium 3.5
SpecificationMoonshotAI Kimi K3Mistral Medium 3.5
MakerMoonshot AIMistral AI
WeightsOpen weightsNo public weights listed
ReleasedJuly 16, 2026April 30, 2026
Context window1.05M262K
Input $/Mtok$3.00$1.50
Output $/Mtok$15.00$7.50
Coding index62.325.5
Independent measurements behind it63
Cost per solved task$0.81$6.02
SourceOpenRouter listingOpenRouter listing

Questions

Is Kimi K3 better than Mistral Medium 3.5 for coding?

Pick Kimi K3 for coding: it scores 62.3 on the Vibe Coding Index against 25.5 for Mistral Medium 3.5. Pick Mistral Medium 3.5 for output tokens 2.0x cheaper ($7.50 vs $15.00 per million).

Which is cheaper, Kimi K3 or Mistral Medium 3.5?

Kimi K3 costs $3.00 per million input tokens and $15.00 per million output tokens; Mistral Medium 3.5 costs $1.50 and $7.50. Per solved SWE-bench Verified task, Kimi K3 costs $0.81 and Mistral Medium 3.5 $6.02.

Which has the bigger context window, Kimi K3 or Mistral Medium 3.5?

Kimi K3, with 1.05M tokens against 262K.

How many benchmarks is the Kimi K3 vs Mistral Medium 3.5 comparison based on?

67 benchmarks have a result for both models as of October 21, 2026. Kimi K3's coding index rests on 6 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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