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DeepSeek V4.1 Flash vs GPT-6 Luna

Updated October 21, 2026. 96 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.

Replace DeepSeek V4.1 Flash Replace GPT-6 Luna
DeepSeek V4.1 FlashDeepSeek
Coding
77.2
Overall
24.7
Output $/M
$0.525
73
GPT-6 LunaOpenAI
Coding
71.4
Overall
38.1
Output $/M
$0.50
22
vs boards won of 96 shared, 1 tied

Decision reading

Pick DeepSeek V4.1 Flash for coding: it scores 77.2 on the Vibe Coding Index against 71.4 for GPT-6 Luna.

Pick GPT-6 Luna when output tokens cost 1.1x less, or when the context window is larger, 1.05M against 1.05M tokens.

Model ADeepSeek V4.1 FlashDeepSeek77.2/1002 independent benchmarksNo cost per solved taskModel BGPT-6 LunaOpenAI71.4/1002 independent benchmarksNo cost per solved task
Shared results
96
DeepSeek V4.1 Flash only
5
GPT-6 Luna only
6
Like-for-like categories
8 of 9

Shared results can support a head-to-head reading. Results only one model has describe coverage, not superiority.

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
DeepSeek V4.1 Flash 77.2 from 2 benchmarks, GPT-6 Luna 71.4 from 2 benchmarks.
Widest category
Math, 12.1 points apart on average over 6 shared benchmarks.
Widest single gap
LiveBench research: DeepSeek V4.1 Flash 86.8% against GPT-6 Luna 43.5%, 43.3 points apart on a 0 to 100 scale.
Output price
DeepSeek V4.1 Flash $0.525 against GPT-6 Luna $0.50 per million output tokens, 1.1x apart.
Context window
DeepSeek V4.1 Flash takes 1.05M tokens, GPT-6 Luna 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.

Boards won, where both have a result
CategoryDeepSeek V4.1 FlashBarsGPT-6 LunaTies
Coding1341 tie
Intelligence02
Agentic work75
Reasoning121
Math24
Knowledge51
Web design72
General273
All shared boards73221 tie
CodingLike-for-likeFour of these boards feed the Vibe Coding Index134
Coding benchmarks for DeepSeek V4.1 Flash and GPT-6 Luna
BenchmarkDeepSeek V4.1 FlashGPT-6 LunaLeader
LiveBench coding90.2%84.5%DeepSeek V4.1 Flash
LMArena WebDev16181578DeepSeek V4.1 Flash
Terminal-Bench 4 (Vals AI)19.7%13.6%DeepSeek V4.1 Flash
Vibe Code Bench (Vals AI)84.7%81.7%DeepSeek V4.1 Flash
Code migration (Vals AI)45.6%42.5%DeepSeek V4.1 Flash
ProgramBench (Vals AI)0.5%0.5%Tie
IOI (Vals AI)40.3%55.6%GPT-6 Luna
Terminal-Bench 2.1 (Vals AI)74.5%73.0%DeepSeek V4.1 Flash
SWE-bench Multimodal (Vals AI)46.5%37.5%DeepSeek V4.1 Flash
Vibe Code Bench 1-100 (Vals AI)16.4%Not measuredOnly DeepSeek V4.1 Flash measured
SkillsBench (Vals AI)69.8%Not measuredOnly DeepSeek V4.1 Flash measured
CyberBench (Vals AI)73.7%76.3%GPT-6 Luna
SciCode51.9%54.6%GPT-6 Luna
FrontierCode43.9%42.4%DeepSeek V4.1 Flash
ALE-Bench1092.31576.9GPT-6 Luna
LMArena Text: coding15021437DeepSeek V4.1 Flash
LMArena Text: software and IT14961423DeepSeek V4.1 Flash
LMArena WebDev: React16281573DeepSeek V4.1 Flash
LMArena WebDev: HTML16121595DeepSeek V4.1 Flash
LMArena WebDev: from an image16061571DeepSeek V4.1 Flash
Neither model has a result on the other 18 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index02
Intelligence benchmarks for DeepSeek V4.1 Flash and GPT-6 Luna
BenchmarkDeepSeek V4.1 FlashGPT-6 LunaLeader
AA Intelligence Index24.738.1GPT-6 Luna
Epoch Capabilities Index155.9156.8GPT-6 Luna
Agentic workLike-for-likePublic boards, shown as published, kept out of the index75
Agentic work benchmarks for DeepSeek V4.1 Flash and GPT-6 Luna
BenchmarkDeepSeek V4.1 FlashGPT-6 LunaLeader
Design Arena: agents building web appsNot measured1189Only GPT-6 Luna measured
Design Arena: agents building full-stack appsNot measured1158Only GPT-6 Luna measured
Design Arena: agents building mobile appsNot measured1133Only GPT-6 Luna measured
LiveBench research86.8%43.5%DeepSeek V4.1 Flash
LiveBench browser84.0%72.0%DeepSeek V4.1 Flash
LiveBench long agentic40.1%48.1%GPT-6 Luna
SREBench (Vals AI)0.8%2.7%GPT-6 Luna
Finance Agent (Vals AI)53.5%49.9%DeepSeek V4.1 Flash
Tax Agent Bench (Vals AI)26.6%19.9%DeepSeek V4.1 Flash
Legal Research Bench (Vals AI)41.4%30.3%DeepSeek V4.1 Flash
Harvey's Legal Agent Benchmark (Vals AI)Not measured4.2%Only GPT-6 Luna measured
Excel Modeling Benchmark (Vals AI)57.2%68.5%GPT-6 Luna
BioMysteryBench (Vals AI)67.8%61.5%DeepSeek V4.1 Flash
Terminal-Bench-Science (Vals AI)0.0%4.3%GPT-6 Luna
Vals Science Index29.6%28.4%DeepSeek V4.1 Flash
APEX-Agents39.5%44.3%GPT-6 Luna
SpireClimbNot measured0.0%Only GPT-6 Luna measured
Neither model has a result on the other 22 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index121
Reasoning benchmarks for DeepSeek V4.1 Flash and GPT-6 Luna
BenchmarkDeepSeek V4.1 FlashGPT-6 LunaLeader
LiveBench reasoning86.7%81.8%DeepSeek V4.1 Flash
MysteryMechanism (Vals AI)21.2%19.4%DeepSeek V4.1 Flash
Humanity's Last Exam (Artificial Analysis run)39.2%38.5%DeepSeek V4.1 Flash
GPQA Diamond (Epoch AI run)89.8%90.5%GPT-6 Luna
ARC-AGI94.5%86.7%DeepSeek V4.1 Flash
ARC-AGI-272.9%59.3%DeepSeek V4.1 Flash
Chess puzzles48.0%36.0%DeepSeek V4.1 Flash
Mystery game puzzles43.0%7.0%DeepSeek V4.1 Flash
LMArena Text: hard prompts14831410DeepSeek V4.1 Flash
LMArena Text: expert15011442DeepSeek V4.1 Flash
LMArena Text: hard prompts in English14881410DeepSeek V4.1 Flash
LMArena Vision: diagrams12971245DeepSeek V4.1 Flash
LMArena Vision: homework13071261DeepSeek V4.1 Flash
Neither model has a result on the other 8 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index24
Math benchmarks for DeepSeek V4.1 Flash and GPT-6 Luna
BenchmarkDeepSeek V4.1 FlashGPT-6 LunaLeader
OTIS Mock AIME98.3%98.9%GPT-6 Luna
FrontierMath, tiers 1 to 367.4%78.9%GPT-6 Luna
FrontierMath, tier 426.8%56.1%GPT-6 Luna
ProofBench54.0%64.0%GPT-6 Luna
LMArena Text: math14781409DeepSeek V4.1 Flash
LMArena Text: mathematical work14851427DeepSeek V4.1 Flash
Neither model has a result on the other 7 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index51
Knowledge benchmarks for DeepSeek V4.1 Flash and GPT-6 Luna
BenchmarkDeepSeek V4.1 FlashGPT-6 LunaLeader
LegalBench (Vals AI)83.3%Not measuredOnly DeepSeek V4.1 Flash measured
MedCode (Vals AI)41.2%44.7%GPT-6 Luna
SimpleQA Verified42.9%41.4%DeepSeek V4.1 Flash
LMArena Text: science14691386DeepSeek V4.1 Flash
LMArena Text: medicine and healthcare14841352DeepSeek V4.1 Flash
LMArena Text: legal and government14431400DeepSeek V4.1 Flash
LMArena Text: business and finance14611388DeepSeek V4.1 Flash
Neither model has a result on the other 10 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index72
Web design benchmarks for DeepSeek V4.1 Flash and GPT-6 Luna
BenchmarkDeepSeek V4.1 FlashGPT-6 LunaLeader
Design Arena: websites13091272DeepSeek V4.1 Flash
Design Arena: UI components13141297DeepSeek V4.1 Flash
Design Arena: game dev13311259DeepSeek V4.1 Flash
Design Arena: data viz12901215DeepSeek V4.1 Flash
Design Arena: 3D13561217DeepSeek V4.1 Flash
Design Arena: all code categories13201271DeepSeek V4.1 Flash
Design Arena: SVG12431253GPT-6 Luna
Design Arena: ASCII art12651156DeepSeek V4.1 Flash
LiveBench design79.2%82.5%GPT-6 Luna
GeneralLike-for-likePublic boards, shown as published, kept out of the index273
General benchmarks for DeepSeek V4.1 Flash and GPT-6 Luna
BenchmarkDeepSeek V4.1 FlashGPT-6 LunaLeader
Vals IndexNot measured52.3%Only GPT-6 Luna measured
LiveBench data analysis79.3%73.4%DeepSeek V4.1 Flash
Public Benefits Bench (Vals AI)64.3%57.6%DeepSeek V4.1 Flash
SAGE (Vals AI)47.9%48.1%GPT-6 Luna
MedScribe (Vals AI)85.5%83.7%DeepSeek V4.1 Flash
Long context reasoning (AA-LCR)84.0%83.3%DeepSeek V4.1 Flash
DTBench89.9%90.1%GPT-6 Luna
LMCA47.0%44.5%DeepSeek V4.1 Flash
Surface Evolver Bench46.3%Not measuredOnly DeepSeek V4.1 Flash measured
Furniture assembly34.2%44.2%GPT-6 Luna
LMArena Text14641389DeepSeek V4.1 Flash
LMArena Text: instruction following14731408DeepSeek V4.1 Flash
LMArena Text: creative writing14371363DeepSeek V4.1 Flash
LMArena Vision12781216DeepSeek V4.1 Flash
LMArena Text: English14731393DeepSeek V4.1 Flash
LMArena Text: non-English14491381DeepSeek V4.1 Flash
LMArena Text: Chinese15011427DeepSeek V4.1 Flash
LMArena Text: German14701376DeepSeek V4.1 Flash
LMArena Text: Japanese14321369DeepSeek V4.1 Flash
LMArena Text: Korean14361359DeepSeek V4.1 Flash
LMArena Text: French14651408DeepSeek V4.1 Flash
LMArena Text: Spanish14591391DeepSeek V4.1 Flash
LMArena Text: Russian14671392DeepSeek V4.1 Flash
LMArena Text: Polish14571383DeepSeek V4.1 Flash
LMArena Text: multi-turn14611392DeepSeek V4.1 Flash
LMArena Text: longer queries14731408DeepSeek V4.1 Flash
LMArena Text: writing and language14501384DeepSeek V4.1 Flash
LMArena Text: entertainment and media14451364DeepSeek V4.1 Flash
LMArena Vision: English12881204DeepSeek V4.1 Flash
LMArena Vision: Chinese13271266DeepSeek V4.1 Flash
LMArena Vision: reading text12821225DeepSeek V4.1 Flash
LMArena Vision: humor1260Not measuredOnly DeepSeek V4.1 Flash measured
LMArena Vision: creative writing12751205DeepSeek V4.1 Flash
Neither model has a result on the other 13 boards here
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
Image generation benchmarks for DeepSeek V4.1 Flash and GPT-6 Luna
BenchmarkDeepSeek V4.1 FlashGPT-6 LunaLeader
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

DeepSeek V4.1 Flash$0.0003Fits in one request
GPT-6 Luna$0.0003Fits in one request

DeepSeek V4.1 Flash costs less

Repository review

50K input + 3K output tokens

DeepSeek V4.1 Flash$0.0040Fits in one request
GPT-6 Luna$0.0065Fits in one request

DeepSeek V4.1 Flash costs less

Agent loop

200K input + 10K output tokens

DeepSeek V4.1 Flash$0.015Fits in one request
GPT-6 Luna$0.025Fits in one request

DeepSeek V4.1 Flash 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 DeepSeek V4.1 Flash and GPT-6 Luna
SpecificationDeepSeek V4.1 FlashOpenAI GPT-6 Luna
MakerDeepSeekOpenAI
WeightsOpen weightsNo public weights listed
ReleasedSeptember 10, 2026September 22, 2026
Context window1.05M1.05M
Input $/Mtok$0.049$0.10
Output $/Mtok$0.525$0.50
Coding index77.271.4
Independent measurements behind it22
Cost per solved taskNot computableNot computable
SourceOpenRouter listingOpenRouter listing

Questions

Is DeepSeek V4.1 Flash better than GPT-6 Luna for coding?

Pick DeepSeek V4.1 Flash for coding: it scores 77.2 on the Vibe Coding Index against 71.4 for GPT-6 Luna. Pick GPT-6 Luna when output tokens cost 1.1x less, or when the context window is larger, 1.05M against 1.05M tokens.

Which is cheaper, DeepSeek V4.1 Flash or GPT-6 Luna?

DeepSeek V4.1 Flash costs $0.049 per million input tokens and $0.525 per million output tokens; GPT-6 Luna costs $0.10 and $0.50. Cost per solved task is known for neither of them.

Which has the bigger context window, DeepSeek V4.1 Flash or GPT-6 Luna?

GPT-6 Luna, with 1.05M tokens against 1.05M.

How many benchmarks is the DeepSeek V4.1 Flash vs GPT-6 Luna comparison based on?

96 benchmarks have a result for both models as of October 21, 2026. DeepSeek V4.1 Flash's coding index rests on 2 independent benchmarks and GPT-6 Luna's on 2. 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/deepseek-v4-1-flash-vs-gpt-6-luna">LLMBenchmark.ai, DeepSeek V4.1 Flash vs GPT-6 Luna</a></p>