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DeepSeek V4 Flash 0423 vs GPT-5.1

Updated October 21, 2026. 46 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.

Replace DeepSeek V4 Flash 0423 Replace GPT-5.1
DeepSeek V4 Flash 0423DeepSeek
Coding
54.6
Overall
24.4
Output $/M
$0.182
11
GPT-5.1OpenAI
Coding
53.3
Overall
24.7
Output $/M
$10.00
35
vs boards won of 46 shared

Decision reading

DeepSeek V4 Flash 0423 and GPT-5.1 are level for coding, 54.6 against 53.3 on the Vibe Coding Index, so price and context decide.

Pick GPT-5.1 when what matters is WeirdML or LMArena Text: software and IT, where it leads. Pick DeepSeek V4 Flash 0423 when output tokens cost 54.9x less, or when the context window is larger, 1.05M against 400K tokens.

Model ADeepSeek V4 Flash 0423DeepSeek54.6/1001 independent benchmarkNo cost per solved taskModel BGPT-5.1OpenAI53.3/1002 independent benchmarks$1.02 per solved task
Shared results
46
DeepSeek V4 Flash 0423 only
2
GPT-5.1 only
54
Like-for-like categories
7 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 Flash 0423 54.6 from 1 benchmark, GPT-5.1 53.3 from 2 benchmarks.
Widest category
Coding, 16.7 points apart on average over 7 shared benchmarks.
Widest single gap
LMArena WebDev: React: DeepSeek V4 Flash 0423 1585 against GPT-5.1 1307, 46.4 points apart on a 0 to 100 scale.
Output price
DeepSeek V4 Flash 0423 $0.182 against GPT-5.1 $10.00 per million output tokens, 54.9x apart.
Context window
DeepSeek V4 Flash 0423 takes 1.05M tokens, GPT-5.1 400K.

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 Flash 0423BarsGPT-5.1Ties
Coding52
Intelligence02
Reasoning04
Math02
Knowledge04
Web design53
General118
All shared boards1135
CodingLike-for-likeFour of these boards feed the Vibe Coding Index52
Coding benchmarks for DeepSeek V4 Flash 0423 and GPT-5.1
BenchmarkDeepSeek V4 Flash 0423GPT-5.1Leader
SWE-bench VerifiedNot measured66.0%Only GPT-5.1 measured
LMArena WebDev15821396DeepSeek V4 Flash 0423
AA Coding Index52.049.4DeepSeek V4 Flash 0423
LiveCodeBench (Vals AI)Not measured86.5%Only GPT-5.1 measured
SWE-bench Verified (Vals AI)Not measured69.8%Only GPT-5.1 measured
Vibe Code Bench (Vals AI)Not measured24.6%Only GPT-5.1 measured
LiveCodeBench (Artificial Analysis run)Not measured86.8%Only GPT-5.1 measured
Terminal-Bench Hard (Artificial Analysis run)Not measured45.5%Only GPT-5.1 measured
Terminal-BenchNot measured47.6%Only GPT-5.1 measured
GSO-BenchNot measured13.7%Only GPT-5.1 measured
WeirdML45.6%60.8%GPT-5.1
ALE-Bench678.2Not measuredOnly DeepSeek V4 Flash 0423 measured
LMArena Text: coding14571453DeepSeek V4 Flash 0423
LMArena Text: software and IT14531454GPT-5.1
LMArena WebDev: React15851307DeepSeek V4 Flash 0423
LMArena WebDev: HTML15581405DeepSeek V4 Flash 0423
LMArena WebDev: from an imageNot measured1421Only GPT-5.1 measured
Neither model has a result on the other 21 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index02
Intelligence benchmarks for DeepSeek V4 Flash 0423 and GPT-5.1
BenchmarkDeepSeek V4 Flash 0423GPT-5.1Leader
AA Intelligence Index24.424.7GPT-5.1
Epoch Capabilities Index146.1149.8GPT-5.1
Agentic workDirectional onlyPublic boards, shown as published, kept out of the index4 boards, none shared
Agentic work benchmarks for DeepSeek V4 Flash 0423 and GPT-5.1
BenchmarkDeepSeek V4 Flash 0423GPT-5.1Leader
AA Agentic Index26.3Not measuredOnly DeepSeek V4 Flash 0423 measured
τ²-Bench TelecomNot measured81.9%Only GPT-5.1 measured
DeepResearch BenchNot measured42.8%Only GPT-5.1 measured
Vending-Bench 2Not measured$1,473Only GPT-5.1 measured
Neither model has a result on the other 35 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index04
Reasoning benchmarks for DeepSeek V4 Flash 0423 and GPT-5.1
BenchmarkDeepSeek V4 Flash 0423GPT-5.1Leader
GPQA DiamondNot measured86.6%Only GPT-5.1 measured
MMMU Pro (Vals AI)Not measured83.2%Only GPT-5.1 measured
GPQA Diamond (Artificial Analysis run)Not measured87.3%Only GPT-5.1 measured
Humanity's Last Exam (Artificial Analysis run)Not measured28.5%Only GPT-5.1 measured
GPQA Diamond (Epoch AI run)Not measured87.6%Only GPT-5.1 measured
ARC-AGINot measured72.8%Only GPT-5.1 measured
ARC-AGI-2Not measured17.6%Only GPT-5.1 measured
SimpleBench46.3%53.2%GPT-5.1
Chess puzzlesNot measured42.0%Only GPT-5.1 measured
Mystery game puzzlesNot measured19.0%Only GPT-5.1 measured
VPCTNot measured58.7%Only GPT-5.1 measured
LMArena Text: hard prompts14441457GPT-5.1
LMArena Text: expert14411470GPT-5.1
LMArena Text: hard prompts in English14491462GPT-5.1
LMArena Vision: diagramsNot measured1264Only GPT-5.1 measured
LMArena Vision: homeworkNot measured1272Only GPT-5.1 measured
Neither model has a result on the other 5 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index02
Math benchmarks for DeepSeek V4 Flash 0423 and GPT-5.1
BenchmarkDeepSeek V4 Flash 0423GPT-5.1Leader
AIMENot measured93.3%Only GPT-5.1 measured
MGSM (Vals AI)Not measured93.0%Only GPT-5.1 measured
AA Math IndexNot measured94.0Only GPT-5.1 measured
AIME 2025 (Artificial Analysis run)Not measured94.0%Only GPT-5.1 measured
OTIS Mock AIMENot measured88.6%Only GPT-5.1 measured
LMArena Text: math14261446GPT-5.1
LMArena Text: mathematical work14321449GPT-5.1
Neither model has a result on the other 6 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index04
Knowledge benchmarks for DeepSeek V4 Flash 0423 and GPT-5.1
BenchmarkDeepSeek V4 Flash 0423GPT-5.1Leader
MMLU ProNot measured86.4%Only GPT-5.1 measured
LegalBench (Vals AI)Not measured85.7%Only GPT-5.1 measured
CaseLaw (Vals AI)Not measured73.4%Only GPT-5.1 measured
CorpFin (Vals AI)Not measured63.8%Only GPT-5.1 measured
TaxEval (Vals AI)Not measured74.9%Only GPT-5.1 measured
MortgageTax (Vals AI)Not measured61.4%Only GPT-5.1 measured
MedQA (Vals AI)Not measured96.4%Only GPT-5.1 measured
MedCode (Vals AI)Not measured52.7%Only GPT-5.1 measured
MMLU Pro (Artificial Analysis run)Not measured87.0%Only GPT-5.1 measured
SimpleQA VerifiedNot measured48.0%Only GPT-5.1 measured
LMArena Text: science14461459GPT-5.1
LMArena Text: medicine and healthcare14481456GPT-5.1
LMArena Text: legal and government14391459GPT-5.1
LMArena Text: business and finance14251431GPT-5.1
Neither model has a result on the other 3 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index53
Web design benchmarks for DeepSeek V4 Flash 0423 and GPT-5.1
BenchmarkDeepSeek V4 Flash 0423GPT-5.1Leader
Design Arena: websites12081187DeepSeek V4 Flash 0423
Design Arena: UI components11641166GPT-5.1
Design Arena: game dev11971179DeepSeek V4 Flash 0423
Design Arena: data viz11271204GPT-5.1
Design Arena: 3D11891061DeepSeek V4 Flash 0423
Design Arena: all code categories12051171DeepSeek V4 Flash 0423
Design Arena: SVG11551149DeepSeek V4 Flash 0423
Design Arena: ASCII art11091118GPT-5.1
Neither model has a result on the other 1 board here
GeneralLike-for-likePublic boards, shown as published, kept out of the index118
General benchmarks for DeepSeek V4 Flash 0423 and GPT-5.1
BenchmarkDeepSeek V4 Flash 0423GPT-5.1Leader
SAGE (Vals AI)Not measured43.2%Only GPT-5.1 measured
MedScribe (Vals AI)Not measured88.1%Only GPT-5.1 measured
IFBenchNot measured72.9%Only GPT-5.1 measured
Long context reasoning (AA-LCR)Not measured80.0%Only GPT-5.1 measured
DTBench86.4%90.1%GPT-5.1
LMCA35.9%43.9%GPT-5.1
CL-benchNot measured23.7%Only GPT-5.1 measured
CL-bench LifeNot measured17.3%Only GPT-5.1 measured
LMArena Text14321443GPT-5.1
LMArena Text: instruction following14211443GPT-5.1
LMArena Text: creative writing14031427GPT-5.1
LMArena VisionNot measured1250Only GPT-5.1 measured
LMArena Text: English14411451GPT-5.1
LMArena Text: non-English14191431GPT-5.1
LMArena Text: Chinese14631495GPT-5.1
LMArena Text: German14191438GPT-5.1
LMArena Text: Japanese13891453GPT-5.1
LMArena Text: Korean13831401GPT-5.1
LMArena Text: French14391450GPT-5.1
LMArena Text: Spanish14361433DeepSeek V4 Flash 0423
LMArena Text: Russian14271435GPT-5.1
LMArena Text: Polish14361440GPT-5.1
LMArena Text: multi-turn14491450GPT-5.1
LMArena Text: longer queries14341448GPT-5.1
LMArena Text: writing and language14101428GPT-5.1
LMArena Text: entertainment and media14001415GPT-5.1
LMArena Vision: EnglishNot measured1252Only GPT-5.1 measured
LMArena Vision: ChineseNot measured1270Only GPT-5.1 measured
LMArena Vision: reading textNot measured1255Only GPT-5.1 measured
LMArena Vision: humorNot measured1263Only GPT-5.1 measured
LMArena Vision: captioningNot measured1252Only GPT-5.1 measured
LMArena Vision: recognizing thingsNot measured1232Only GPT-5.1 measured
LMArena Vision: creative writingNot measured1266Only GPT-5.1 measured
LMArena DocumentNot measured1403Only GPT-5.1 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 DeepSeek V4 Flash 0423 and GPT-5.1
BenchmarkDeepSeek V4 Flash 0423GPT-5.1Leader
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 Flash 0423$0.0002Fits in one request
GPT-5.1$0.0063Fits in one request

DeepSeek V4 Flash 0423 costs less

Repository review

50K input + 3K output tokens

DeepSeek V4 Flash 0423$0.0051Fits in one request
GPT-5.1$0.092Fits in one request

DeepSeek V4 Flash 0423 costs less

Agent loop

200K input + 10K output tokens

DeepSeek V4 Flash 0423$0.020Fits in one request
GPT-5.1$0.350Fits in one request

DeepSeek V4 Flash 0423 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 Flash 0423 and GPT-5.1
SpecificationDeepSeek V4 Flash 0423OpenAI GPT-5.1
MakerDeepSeekOpenAI
WeightsOpen weightsNo public weights listed
ReleasedApril 24, 2026November 13, 2025
Context window1.05M400K
Input $/Mtok$0.091$1.25
Output $/Mtok$0.182$10.00
Coding index54.653.3
Independent measurements behind it12
Cost per solved taskNot computable$1.02
SourceOpenRouter listingOpenRouter listing

Questions

Is DeepSeek V4 Flash 0423 better than GPT-5.1 for coding?

DeepSeek V4 Flash 0423 and GPT-5.1 are level for coding, 54.6 against 53.3 on the Vibe Coding Index, so price and context decide. Pick GPT-5.1 when what matters is WeirdML or LMArena Text: software and IT, where it leads. Pick DeepSeek V4 Flash 0423 when output tokens cost 54.9x less, or when the context window is larger, 1.05M against 400K tokens.

Which is cheaper, DeepSeek V4 Flash 0423 or GPT-5.1?

DeepSeek V4 Flash 0423 costs $0.091 per million input tokens and $0.182 per million output tokens; GPT-5.1 costs $1.25 and $10.00. Cost per solved task is known for GPT-5.1 only.

Which has the bigger context window, DeepSeek V4 Flash 0423 or GPT-5.1?

DeepSeek V4 Flash 0423, with 1.05M tokens against 400K.

How many benchmarks is the DeepSeek V4 Flash 0423 vs GPT-5.1 comparison based on?

46 benchmarks have a result for both models as of October 21, 2026. DeepSeek V4 Flash 0423's coding index rests on 1 independent benchmark and GPT-5.1's on 2. Where only one model has a result, the page says so instead of naming a winner.

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