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GPT-4.1 Nano vs GPT-5.1

Updated October 21, 2026. 65 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.

Replace GPT-4.1 Nano Replace GPT-5.1
GPT-4.1 NanoOpenAI
Coding
8.9
Overall
7.8
Output $/M
$0.40
0
GPT-5.1OpenAI
Coding
53.3
Overall
24.7
Output $/M
$10.00
65
vs boards won of 65 shared

Decision reading

Pick GPT-5.1 for coding: it scores 53.3 on the Vibe Coding Index against 8.9 for GPT-4.1 Nano.

Pick GPT-4.1 Nano when output tokens cost 25.0x less, or when the context window is larger, 1.05M against 400K tokens.

Model AGPT-4.1 NanoOpenAI8.9/1001 independent benchmarkNo cost per solved taskModel BGPT-5.1OpenAI53.3/1002 independent benchmarks$1.02 per solved task
Shared results
65
GPT-4.1 Nano only
4
GPT-5.1 only
35
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
GPT-4.1 Nano 8.9 from 1 benchmark, GPT-5.1 53.3 from 2 benchmarks.
Widest category
Agentic work, 64.6 points apart on average over 1 shared benchmark.
Widest single gap
ARC-AGI: GPT-4.1 Nano 0.0% against GPT-5.1 72.8%, 72.8 points apart on a 0 to 100 scale.
Output price
GPT-4.1 Nano $0.40 against GPT-5.1 $10.00 per million output tokens, 25.0x apart.
Context window
GPT-4.1 Nano 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
CategoryGPT-4.1 NanoBarsGPT-5.1Ties
Coding07
Intelligence02
Agentic work01
Reasoning011
Math07
Knowledge012
Web design06
General019
All shared boards065
CodingLike-for-likeFour of these boards feed the Vibe Coding Index07
Coding benchmarks for GPT-4.1 Nano and GPT-5.1
BenchmarkGPT-4.1 NanoGPT-5.1Leader
Aider polyglot8.9%Not measuredOnly GPT-4.1 Nano measured
SWE-bench VerifiedNot measured66.0%Only GPT-5.1 measured
LMArena WebDevNot measured1396Only GPT-5.1 measured
AA Coding Index11.149.4GPT-5.1
LiveCodeBench (Vals AI)42.7%86.5%GPT-5.1
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)32.6%86.8%GPT-5.1
Terminal-Bench Hard (Artificial Analysis run)3.8%45.5%GPT-5.1
Terminal-BenchNot measured47.6%Only GPT-5.1 measured
GSO-BenchNot measured13.7%Only GPT-5.1 measured
WeirdML19.0%60.8%GPT-5.1
LMArena Text: coding13061453GPT-5.1
LMArena Text: software and IT13051454GPT-5.1
LMArena WebDev: ReactNot measured1307Only GPT-5.1 measured
LMArena WebDev: HTMLNot measured1405Only GPT-5.1 measured
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 GPT-4.1 Nano and GPT-5.1
BenchmarkGPT-4.1 NanoGPT-5.1Leader
AA Intelligence Index7.824.7GPT-5.1
Epoch Capabilities Index129.5149.8GPT-5.1
Agentic workLike-for-likePublic boards, shown as published, kept out of the index01
Agentic work benchmarks for GPT-4.1 Nano and GPT-5.1
BenchmarkGPT-4.1 NanoGPT-5.1Leader
τ²-Bench Telecom17.3%81.9%GPT-5.1
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 36 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index011
Reasoning benchmarks for GPT-4.1 Nano and GPT-5.1
BenchmarkGPT-4.1 NanoGPT-5.1Leader
GPQA Diamond50.8%86.6%GPT-5.1
MMMU Pro (Vals AI)55.0%83.2%GPT-5.1
GPQA Diamond (Artificial Analysis run)51.2%87.3%GPT-5.1
Humanity's Last Exam (Artificial Analysis run)3.8%28.5%GPT-5.1
GPQA Diamond (Epoch AI run)48.9%87.6%GPT-5.1
ARC-AGI0.0%72.8%GPT-5.1
ARC-AGI-20.0%17.6%GPT-5.1
SimpleBenchNot measured53.2%Only GPT-5.1 measured
Chess puzzles0.0%42.0%GPT-5.1
Mystery game puzzlesNot measured19.0%Only GPT-5.1 measured
VPCTNot measured58.7%Only GPT-5.1 measured
LMArena Text: hard prompts12861457GPT-5.1
LMArena Text: expert12711470GPT-5.1
LMArena Text: hard prompts in English12931462GPT-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 index07
Math benchmarks for GPT-4.1 Nano and GPT-5.1
BenchmarkGPT-4.1 NanoGPT-5.1Leader
AIME26.5%93.3%GPT-5.1
MATH 500 (Vals AI)80.2%Not measuredOnly GPT-4.1 Nano measured
MGSM (Vals AI)69.3%93.0%GPT-5.1
AA Math Index24.094.0GPT-5.1
AIME 2025 (Artificial Analysis run)24.0%94.0%GPT-5.1
OTIS Mock AIME28.9%88.6%GPT-5.1
MATH level 570.0%Not measuredOnly GPT-4.1 Nano measured
LMArena Text: math12741446GPT-5.1
LMArena Text: mathematical work12741449GPT-5.1
Neither model has a result on the other 4 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index012
Knowledge benchmarks for GPT-4.1 Nano and GPT-5.1
BenchmarkGPT-4.1 NanoGPT-5.1Leader
MMLU Pro63.5%86.4%GPT-5.1
LegalBench (Vals AI)61.1%85.7%GPT-5.1
CaseLaw (Vals AI)Not measured73.4%Only GPT-5.1 measured
CorpFin (Vals AI)42.1%63.8%GPT-5.1
TaxEval (Vals AI)60.8%74.9%GPT-5.1
MortgageTax (Vals AI)52.8%61.4%GPT-5.1
MedQA (Vals AI)68.2%96.4%GPT-5.1
MedCode (Vals AI)Not measured52.7%Only GPT-5.1 measured
MMLU Pro (Artificial Analysis run)65.7%87.0%GPT-5.1
SimpleQA Verified6.0%48.0%GPT-5.1
LMArena Text: science12971459GPT-5.1
LMArena Text: medicine and healthcare12761456GPT-5.1
LMArena Text: legal and government13001459GPT-5.1
LMArena Text: business and finance12671431GPT-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 index06
Web design benchmarks for GPT-4.1 Nano and GPT-5.1
BenchmarkGPT-4.1 NanoGPT-5.1Leader
Design Arena: websites9731187GPT-5.1
Design Arena: UI components9161166GPT-5.1
Design Arena: game dev9711179GPT-5.1
Design Arena: data viz8911204GPT-5.1
Design Arena: 3D9251061GPT-5.1
Design Arena: all code categories9631171GPT-5.1
Design Arena: SVGNot measured1149Only GPT-5.1 measured
Design Arena: ASCII artNot measured1118Only GPT-5.1 measured
Neither model has a result on the other 1 board here
GeneralLike-for-likePublic boards, shown as published, kept out of the index019
General benchmarks for GPT-4.1 Nano and GPT-5.1
BenchmarkGPT-4.1 NanoGPT-5.1Leader
SAGE (Vals AI)Not measured43.2%Only GPT-5.1 measured
MedScribe (Vals AI)Not measured88.1%Only GPT-5.1 measured
IFBench32.0%72.9%GPT-5.1
Long context reasoning (AA-LCR)20.3%80.0%GPT-5.1
DTBench52.5%90.1%GPT-5.1
LMCA5.5%43.9%GPT-5.1
Fiction.LiveBench25.0%Not measuredOnly GPT-4.1 Nano measured
CL-benchNot measured23.7%Only GPT-5.1 measured
CL-bench LifeNot measured17.3%Only GPT-5.1 measured
LMArena Text12851443GPT-5.1
LMArena Text: instruction following12661443GPT-5.1
LMArena Text: creative writing12601427GPT-5.1
LMArena Vision10631250GPT-5.1
LMArena Text: English13031451GPT-5.1
LMArena Text: non-English12601431GPT-5.1
LMArena Text: Chinese12701495GPT-5.1
LMArena Text: German12881438GPT-5.1
LMArena Text: Japanese11981453GPT-5.1
LMArena Text: KoreanNot measured1401Only GPT-5.1 measured
LMArena Text: FrenchNot measured1450Only GPT-5.1 measured
LMArena Text: SpanishNot measured1433Only GPT-5.1 measured
LMArena Text: Russian12611435GPT-5.1
LMArena Text: PolishNot measured1440Only GPT-5.1 measured
LMArena Text: multi-turn12771450GPT-5.1
LMArena Text: longer queries12831448GPT-5.1
LMArena Text: writing and language12611428GPT-5.1
LMArena Text: entertainment and media12431415GPT-5.1
LMArena Vision: English11011252GPT-5.1
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 11 boards here
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
Image generation benchmarks for GPT-4.1 Nano and GPT-5.1
BenchmarkGPT-4.1 NanoGPT-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

GPT-4.1 Nano$0.0003Fits in one request
GPT-5.1$0.0063Fits in one request

GPT-4.1 Nano costs less

Repository review

50K input + 3K output tokens

GPT-4.1 Nano$0.0062Fits in one request
GPT-5.1$0.092Fits in one request

GPT-4.1 Nano costs less

Agent loop

200K input + 10K output tokens

GPT-4.1 Nano$0.024Fits in one request
GPT-5.1$0.350Fits in one request

GPT-4.1 Nano 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 GPT-4.1 Nano and GPT-5.1
SpecificationOpenAI GPT-4.1 NanoOpenAI GPT-5.1
MakerOpenAIOpenAI
WeightsNo public weights listedNo public weights listed
ReleasedApril 14, 2025November 13, 2025
Context window1.05M400K
Input $/Mtok$0.10$1.25
Output $/Mtok$0.40$10.00
Coding index8.953.3
Independent measurements behind it12
Cost per solved taskNot computable$1.02
SourceOpenRouter listingOpenRouter listing

Questions

Is GPT-4.1 Nano better than GPT-5.1 for coding?

Pick GPT-5.1 for coding: it scores 53.3 on the Vibe Coding Index against 8.9 for GPT-4.1 Nano. Pick GPT-4.1 Nano when output tokens cost 25.0x less, or when the context window is larger, 1.05M against 400K tokens.

Which is cheaper, GPT-4.1 Nano or GPT-5.1?

GPT-4.1 Nano costs $0.10 per million input tokens and $0.40 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, GPT-4.1 Nano or GPT-5.1?

GPT-4.1 Nano, with 1.05M tokens against 400K.

How many benchmarks is the GPT-4.1 Nano vs GPT-5.1 comparison based on?

65 benchmarks have a result for both models as of October 21, 2026. GPT-4.1 Nano'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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