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GPT-5.1 vs GPT-5 Nano

GPT-5.1 leads GPT-5 Nano on the Artificial Analysis Intelligence Index, 24.7 to 13.0, and GPT-5 Nano costs 25.0x less per output token ($0.40 vs $10.00 per million). Updated October 22, 2026; 79 benchmarks have a result for both.

Replace GPT-5.1 Replace GPT-5 Nano
GPT-5.1OpenAI
Coding
40.4
Overall
55.0
Output $/M
$10.00
79
GPT-5 NanoOpenAI
Coding
No data
Overall
35.6
Output $/M
$0.40
0
vs boards won of 79 shared

GPT-5.1 or GPT-5 Nano: which to pick

Only GPT-5.1 has a coding score, 40.4 on the Vibe Coding Index; GPT-5 Nano has none, so the two cannot be ranked on coding.

Pick GPT-5 Nano for output tokens 25.0x cheaper ($0.40 vs $10.00 per million) and a lower cost per solved task ($0.109 against $1.02).

Model AGPT-5.1OpenAI40.4/1003 independent benchmarks$1.02 per solved taskModel BGPT-5 NanoOpenAINot benchmarkedNo coding benchmark$0.109 per solved task
Shared results
79
GPT-5.1 only
22
GPT-5 Nano only
8
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
GPT-5.1 40.4 from 3 benchmarks, GPT-5 Nano not benchmarked.
Widest category
Agentic work, 45.3 points apart on average over 1 shared benchmark.
Widest single gap
ARC-AGI: GPT-5.1 72.8% against GPT-5 Nano 20.7%, 52.1 points apart on a 0 to 100 scale.
Output price
GPT-5.1 $10.00 against GPT-5 Nano $0.40 per million output tokens, 25.0x apart.
Context window
Both take 400K tokens.

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-5.1BarsGPT-5 NanoTies
Coding80
Intelligence20
Agentic work10
Reasoning150
Math70
Knowledge130
Web design60
General270
All shared boards790
CodingLike-for-likeSix of these boards feed the Vibe Coding Index80
Coding benchmarks for GPT-5.1 and GPT-5 Nano
BenchmarkGPT-5.1GPT-5 NanoLeader
SWE-bench Verified66.0%34.8%GPT-5.1
LMArena WebDev1396Not measuredOnly GPT-5.1 measured
AA Coding Index49.4Not measuredOnly GPT-5.1 measured
LiveCodeBench (Vals AI)86.5%70.2%GPT-5.1
SWE-bench Verified (Vals AI)69.8%Not measuredOnly GPT-5.1 measured
Vibe Code Bench (Vals AI)24.6%Not measuredOnly GPT-5.1 measured
LiveCodeBench (Artificial Analysis run)86.8%78.9%GPT-5.1
Terminal-Bench Hard (Artificial Analysis run)45.5%17.4%GPT-5.1
Terminal-Bench47.6%21.8%GPT-5.1
GSO-Bench13.7%Not measuredOnly GPT-5.1 measured
WeirdML60.8%38.1%GPT-5.1
LMArena Text: coding14531351GPT-5.1
LMArena Text: software and IT14541345GPT-5.1
LMArena WebDev: React1307Not measuredOnly GPT-5.1 measured
LMArena WebDev: HTML1405Not measuredOnly GPT-5.1 measured
LMArena WebDev: from an image1421Not measuredOnly GPT-5.1 measured
Neither model has a result on the other 23 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index20
Intelligence benchmarks for GPT-5.1 and GPT-5 Nano
BenchmarkGPT-5.1GPT-5 NanoLeader
AA Intelligence Index24.713.0GPT-5.1
Epoch Capabilities Index149.8139.2GPT-5.1
Agentic workLike-for-likePublic boards, shown as published, kept out of the index10
Agentic work benchmarks for GPT-5.1 and GPT-5 Nano
BenchmarkGPT-5.1GPT-5 NanoLeader
τ²-Bench Telecom81.9%36.5%GPT-5.1
DeepResearch Bench42.8%Not measuredOnly GPT-5.1 measured
Vending-Bench 2$1,473Not measuredOnly GPT-5.1 measured
Berkeley Function Calling Leaderboard (BFCL)Not measured51.4%Only GPT-5 Nano measured
Neither model has a result on the other 37 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index150
Reasoning benchmarks for GPT-5.1 and GPT-5 Nano
BenchmarkGPT-5.1GPT-5 NanoLeader
GPQA Diamond86.6%63.4%GPT-5.1
MMMU Pro (Vals AI)83.2%70.9%GPT-5.1
GPQA Diamond (Artificial Analysis run)87.3%67.6%GPT-5.1
Humanity's Last Exam (Artificial Analysis run)28.5%9.5%GPT-5.1
GPQA Diamond (Epoch AI run)87.6%69.4%GPT-5.1
ARC-AGI72.8%20.7%GPT-5.1
ARC-AGI-217.6%2.6%GPT-5.1
SimpleBench53.2%Not measuredOnly GPT-5.1 measured
Chess puzzles42.0%22.0%GPT-5.1
Mystery game puzzles19.0%9.0%GPT-5.1
VPCT58.7%37.2%GPT-5.1
LMArena Text: hard prompts14571328GPT-5.1
LMArena Text: expert14701321GPT-5.1
LMArena Text: hard prompts in English14621338GPT-5.1
LMArena Vision: diagrams12641141GPT-5.1
LMArena Vision: homework12721157GPT-5.1
Kagi LLM BenchmarkNot measured62.2%Only GPT-5 Nano measured
Neither model has a result on the other 5 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index70
Math benchmarks for GPT-5.1 and GPT-5 Nano
BenchmarkGPT-5.1GPT-5 NanoLeader
AIME93.3%81.2%GPT-5.1
MATH 500 (Vals AI)Not measured93.8%Only GPT-5 Nano measured
MGSM (Vals AI)93.0%89.3%GPT-5.1
AA Math Index94.083.7GPT-5.1
AIME 2025 (Artificial Analysis run)94.0%83.7%GPT-5.1
OTIS Mock AIME88.6%81.1%GPT-5.1
FrontierMath, tiers 1 to 3Not measured20.0%Only GPT-5 Nano measured
FrontierMath, tier 4Not measured2.4%Only GPT-5 Nano measured
ProofBenchNot measured12.0%Only GPT-5 Nano measured
MATH level 5Not measured95.2%Only GPT-5 Nano measured
LMArena Text: math14461317GPT-5.1
LMArena Text: mathematical work14491326GPT-5.1
Neither model has a result on the other 1 board here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index130
Knowledge benchmarks for GPT-5.1 and GPT-5 Nano
BenchmarkGPT-5.1GPT-5 NanoLeader
MMLU Pro86.4%76.1%GPT-5.1
LegalBench (Vals AI)85.7%50.1%GPT-5.1
CaseLaw (Vals AI)73.4%52.6%GPT-5.1
CorpFin (Vals AI)63.8%Not measuredOnly GPT-5.1 measured
TaxEval (Vals AI)74.9%67.4%GPT-5.1
MortgageTax (Vals AI)61.4%53.6%GPT-5.1
MedQA (Vals AI)96.4%93.3%GPT-5.1
MedCode (Vals AI)52.7%30.4%GPT-5.1
MMLU Pro (Artificial Analysis run)87.0%78.0%GPT-5.1
SimpleQA Verified48.0%11.7%GPT-5.1
LMArena Text: science14591318GPT-5.1
LMArena Text: medicine and healthcare14561335GPT-5.1
LMArena Text: legal and government14591298GPT-5.1
LMArena Text: business and finance14311311GPT-5.1
FACTS Benchmark Suite45.0%Not measuredOnly GPT-5.1 measured
Neither model has a result on the other 3 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index60
Web design benchmarks for GPT-5.1 and GPT-5 Nano
BenchmarkGPT-5.1GPT-5 NanoLeader
Design Arena: websites11871101GPT-5.1
Design Arena: UI components11631064GPT-5.1
Design Arena: game dev11781044GPT-5.1
Design Arena: data viz12041056GPT-5.1
Design Arena: 3D1060965GPT-5.1
Design Arena: all code categories11701084GPT-5.1
Design Arena: SVG1149Not measuredOnly GPT-5.1 measured
Design Arena: ASCII art1119Not measuredOnly 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 index270
General benchmarks for GPT-5.1 and GPT-5 Nano
BenchmarkGPT-5.1GPT-5 NanoLeader
SAGE (Vals AI)43.2%30.4%GPT-5.1
MedScribe (Vals AI)88.1%72.9%GPT-5.1
IFBench72.9%67.6%GPT-5.1
Long context reasoning (AA-LCR)80.0%45.0%GPT-5.1
DTBench90.1%62.7%GPT-5.1
LMCA43.9%7.9%GPT-5.1
Fiction.LiveBenchNot measured44.4%Only GPT-5 Nano measured
CL-bench23.7%Not measuredOnly GPT-5.1 measured
CL-bench Life17.3%Not measuredOnly GPT-5.1 measured
LMArena Text14431320GPT-5.1
LMArena Text: instruction following14431306GPT-5.1
LMArena Text: creative writing14271249GPT-5.1
LMArena Vision12501159GPT-5.1
LMArena Text: English14511321GPT-5.1
LMArena Text: non-English14311313GPT-5.1
LMArena Text: Chinese14951356GPT-5.1
LMArena Text: German14381327GPT-5.1
LMArena Text: Japanese14531227GPT-5.1
LMArena Text: Korean14011269GPT-5.1
LMArena Text: French1450Not measuredOnly GPT-5.1 measured
LMArena Text: Spanish14331360GPT-5.1
LMArena Text: Russian14351296GPT-5.1
LMArena Text: Polish14401314GPT-5.1
LMArena Text: multi-turn14501311GPT-5.1
LMArena Text: longer queries14481312GPT-5.1
LMArena Text: writing and language14281283GPT-5.1
LMArena Text: entertainment and media14151268GPT-5.1
LMArena Vision: English12521170GPT-5.1
LMArena Vision: Chinese12701176GPT-5.1
LMArena Vision: reading text12551152GPT-5.1
LMArena Vision: humor12631110GPT-5.1
LMArena Vision: captioning1252Not measuredOnly GPT-5.1 measured
LMArena Vision: recognizing things1232Not measuredOnly GPT-5.1 measured
LMArena Vision: creative writing1266Not measuredOnly GPT-5.1 measured
LMArena Document1403Not measuredOnly 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-5.1 and GPT-5 Nano
BenchmarkGPT-5.1GPT-5 NanoLeader
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-5.1$0.0063Fits in one request
GPT-5 Nano$0.0003Fits in one request

GPT-5 Nano costs less

Repository review

50K input + 3K output tokens

GPT-5.1$0.092Fits in one request
GPT-5 Nano$0.0037Fits in one request

GPT-5 Nano costs less

Agent loop

200K input + 10K output tokens

GPT-5.1$0.350Fits in one request
GPT-5 Nano$0.014Fits in one request

GPT-5 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-5.1 and GPT-5 Nano
SpecificationOpenAI GPT-5.1OpenAI GPT-5 Nano
MakerOpenAIOpenAI
WeightsNo public weights listedNo public weights listed
ReleasedNovember 13, 2025August 7, 2025
Context window400K400K
Input $/Mtok$1.25$0.05
Output $/Mtok$10.00$0.40
Coding index40.4Not benchmarked
Independent measurements behind it30
Cost per solved task$1.02$0.109
SourceOpenRouter listingOpenRouter listing

Questions

Is GPT-5.1 better than GPT-5 Nano for coding?

Only GPT-5.1 has a coding score, 40.4 on the Vibe Coding Index; GPT-5 Nano has none, so the two cannot be ranked on coding. Pick GPT-5 Nano for output tokens 25.0x cheaper ($0.40 vs $10.00 per million) and a lower cost per solved task ($0.109 against $1.02).

Which is cheaper, GPT-5.1 or GPT-5 Nano?

GPT-5.1 costs $1.25 per million input tokens and $10.00 per million output tokens; GPT-5 Nano costs $0.05 and $0.40. Per solved SWE-bench Verified task, GPT-5.1 costs $1.02 and GPT-5 Nano $0.109.

Which has the bigger context window, GPT-5.1 or GPT-5 Nano?

Neither: both take 400K tokens.

How many benchmarks is the GPT-5.1 vs GPT-5 Nano comparison based on?

79 benchmarks have a result for both models as of October 22, 2026. GPT-5.1's coding index rests on 3 independent benchmarks and GPT-5 Nano's on 0. Where only one model has a result, the page says so instead of naming a winner.

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