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GPT-4.1 Nano vs gpt-oss-20b

gpt-oss-20b leads GPT-4.1 Nano on the Artificial Analysis Intelligence Index, 10.0 to 7.8, and gpt-oss-20b costs 2.7x less per output token ($0.15 vs $0.40 per million). Updated October 23, 2026; 54 benchmarks have a result for both.

Replace GPT-4.1 Nano Replace gpt-oss-20b
GPT-4.1 NanoOpenAI
Coding
No data
Overall
24.7
Output $/M
$0.40
14
gpt-oss-20bOpenAI
Coding
No data
Overall
38.5
Output $/M
$0.15
40
vs boards won of 54 shared

GPT-4.1 Nano or gpt-oss-20b: which to pick

Neither model has a coding score yet, so the two cannot be ranked on coding.

Pick GPT-4.1 Nano for a larger context window (1.05M against 131K tokens) and work measured by LiveCodeBench (Vals AI) or LiveCodeBench (Artificial Analysis run), where it leads.

Model AGPT-4.1 NanoOpenAINot benchmarkedNo coding benchmarkNo cost per solved taskModel Bgpt-oss-20bOpenAINot benchmarkedNo coding benchmarkNo cost per solved task
Shared results
54
GPT-4.1 Nano only
17
gpt-oss-20b only
9
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-4.1 Nano not benchmarked, gpt-oss-20b not benchmarked.
Widest category
Agentic work, 43.0 points apart on average over 1 shared benchmark.
Widest single gap
AIME 2025 (Artificial Analysis run): GPT-4.1 Nano 24.0% against gpt-oss-20b 89.3%, 65.3 points apart on a 0 to 100 scale.
Output price
GPT-4.1 Nano $0.40 against gpt-oss-20b $0.15 per million output tokens, 2.7x apart.
Context window
GPT-4.1 Nano takes 1.05M tokens, gpt-oss-20b 131K.

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-oss-20bTies
Coding06
Intelligence02
Agentic work01
Reasoning35
Math08
Knowledge28
Web design11
General89
All shared boards1440
CodingLike-for-likeSix of these boards feed the Vibe Coding Index06
Coding benchmarks for GPT-4.1 Nano and gpt-oss-20b
BenchmarkGPT-4.1 Nanogpt-oss-20bLeader
Aider polyglot8.9%Not measuredOnly GPT-4.1 Nano measured
AA Coding Index11.1Not measuredOnly GPT-4.1 Nano measured
LiveCodeBench (Vals AI)42.7%80.4%gpt-oss-20b
LiveCodeBench (Artificial Analysis run)32.6%77.7%gpt-oss-20b
SciCodeNot measured38.9%Only gpt-oss-20b measured
Terminal-Bench Hard (Artificial Analysis run)3.8%10.6%gpt-oss-20b
Terminal-BenchNot measured3.4%Only gpt-oss-20b measured
WeirdML19.0%40.9%gpt-oss-20b
ALE-BenchNot measured566.0Only gpt-oss-20b measured
LMArena Text: coding13051306gpt-oss-20b
LMArena Text: software and IT13051311gpt-oss-20b
Neither model has a result on the other 32 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index02
Intelligence benchmarks for GPT-4.1 Nano and gpt-oss-20b
BenchmarkGPT-4.1 Nanogpt-oss-20bLeader
AA Intelligence Index7.810.0gpt-oss-20b
Epoch Capabilities Index129.5137.7gpt-oss-20b
Agentic workLike-for-likePublic boards, shown as published, kept out of the index01
Agentic work benchmarks for GPT-4.1 Nano and gpt-oss-20b
BenchmarkGPT-4.1 Nanogpt-oss-20bLeader
τ²-Bench Telecom17.3%60.2%gpt-oss-20b
Berkeley Function Calling Leaderboard (BFCL)33.1%Not measuredOnly GPT-4.1 Nano measured
BrowseComp-PlusNot measured50.6%Only gpt-oss-20b measured
Neither model has a result on the other 39 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index35
Reasoning benchmarks for GPT-4.1 Nano and gpt-oss-20b
BenchmarkGPT-4.1 Nanogpt-oss-20bLeader
GPQA Diamond50.8%68.9%gpt-oss-20b
MMMU Pro (Vals AI)55.0%Not measuredOnly GPT-4.1 Nano measured
GPQA Diamond (Artificial Analysis run)51.2%68.8%gpt-oss-20b
Humanity's Last Exam (Artificial Analysis run)3.8%11.0%gpt-oss-20b
GPQA Diamond (Epoch AI run)48.9%60.8%gpt-oss-20b
ARC-AGI0.0%Not measuredOnly GPT-4.1 Nano measured
ARC-AGI-20.0%Not measuredOnly GPT-4.1 Nano measured
Chess puzzles0.0%Not measuredOnly GPT-4.1 Nano measured
LMArena Text: hard prompts12861274GPT-4.1 Nano
LMArena Text: expert12721258GPT-4.1 Nano
LMArena Text: hard prompts in English12921292GPT-4.1 Nano
Kagi LLM Benchmark33.3%53.2%gpt-oss-20b
Neither model has a result on the other 11 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index08
Math benchmarks for GPT-4.1 Nano and gpt-oss-20b
BenchmarkGPT-4.1 Nanogpt-oss-20bLeader
AIME26.5%86.0%gpt-oss-20b
MATH 500 (Vals AI)80.2%94.2%gpt-oss-20b
MGSM (Vals AI)69.3%89.0%gpt-oss-20b
AA Math Index24.089.3gpt-oss-20b
AIME 2025 (Artificial Analysis run)24.0%89.3%gpt-oss-20b
OTIS Mock AIME28.9%65.3%gpt-oss-20b
MATH level 570.0%Not measuredOnly GPT-4.1 Nano measured
LMArena Text: math12741317gpt-oss-20b
LMArena Text: mathematical work12741305gpt-oss-20b
MathArenaNot measured12.8%Only gpt-oss-20b measured
Neither model has a result on the other 4 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index28
Knowledge benchmarks for GPT-4.1 Nano and gpt-oss-20b
BenchmarkGPT-4.1 Nanogpt-oss-20bLeader
MMLU Pro63.5%71.6%gpt-oss-20b
LegalBench (Vals AI)61.1%70.8%gpt-oss-20b
CaseLaw (Vals AI)Not measured43.8%Only gpt-oss-20b measured
CorpFin (Vals AI)42.1%53.1%gpt-oss-20b
TaxEval (Vals AI)60.8%63.7%gpt-oss-20b
MortgageTax (Vals AI)52.8%Not measuredOnly GPT-4.1 Nano measured
MedQA (Vals AI)68.2%82.9%gpt-oss-20b
MMLU Pro (Artificial Analysis run)65.7%74.8%gpt-oss-20b
SimpleQA Verified6.0%Not measuredOnly GPT-4.1 Nano measured
LMArena Text: science12971296GPT-4.1 Nano
LMArena Text: medicine and healthcare12761310gpt-oss-20b
LMArena Text: legal and government13001280GPT-4.1 Nano
LMArena Text: business and finance12661283gpt-oss-20b
Neither model has a result on the other 7 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index11
Web design benchmarks for GPT-4.1 Nano and gpt-oss-20b
BenchmarkGPT-4.1 Nanogpt-oss-20bLeader
Design Arena: websites973852GPT-4.1 Nano
Design Arena: UI components913Not measuredOnly GPT-4.1 Nano measured
Design Arena: game dev970Not measuredOnly GPT-4.1 Nano measured
Design Arena: data viz891933gpt-oss-20b
Design Arena: 3D926Not measuredOnly GPT-4.1 Nano measured
Design Arena: all code categories962Not measuredOnly GPT-4.1 Nano measured
Neither model has a result on the other 3 boards here
GeneralLike-for-likePublic boards, shown as published, kept out of the index89
General benchmarks for GPT-4.1 Nano and gpt-oss-20b
BenchmarkGPT-4.1 Nanogpt-oss-20bLeader
IFBench32.0%65.1%gpt-oss-20b
Long context reasoning (AA-LCR)20.3%34.7%gpt-oss-20b
DTBench52.5%68.0%gpt-oss-20b
LMCA5.5%14.5%gpt-oss-20b
Fiction.LiveBench25.0%Not measuredOnly GPT-4.1 Nano measured
LMArena Text12851287gpt-oss-20b
LMArena Text: instruction following12661236GPT-4.1 Nano
LMArena Text: creative writing12601201GPT-4.1 Nano
LMArena Vision1063Not measuredOnly GPT-4.1 Nano measured
LMArena Text: English13031303GPT-4.1 Nano
LMArena Text: non-English12601268gpt-oss-20b
LMArena Text: Chinese12701315gpt-oss-20b
LMArena Text: German12881255GPT-4.1 Nano
LMArena Text: Japanese11981244gpt-oss-20b
LMArena Text: KoreanNot measured1234Only gpt-oss-20b measured
LMArena Text: SpanishNot measured1267Only gpt-oss-20b measured
LMArena Text: Russian12611278gpt-oss-20b
LMArena Text: PolishNot measured1252Only gpt-oss-20b measured
LMArena Text: multi-turn12771268GPT-4.1 Nano
LMArena Text: longer queries12821250GPT-4.1 Nano
LMArena Text: writing and language12611238GPT-4.1 Nano
LMArena Text: entertainment and media12431216GPT-4.1 Nano
LMArena Vision: English1101Not measuredOnly GPT-4.1 Nano measured
Neither model has a result on the other 25 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-oss-20b
BenchmarkGPT-4.1 Nanogpt-oss-20bLeader
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-oss-20b$0.0001Fits in one request

gpt-oss-20b costs less

Repository review

50K input + 3K output tokens

GPT-4.1 Nano$0.0062Fits in one request
gpt-oss-20b$0.0019Fits in one request

gpt-oss-20b costs less

Agent loop

200K input + 10K output tokens

GPT-4.1 Nano$0.024Fits in one request
gpt-oss-20b$0.0075Exceeds the context window

gpt-oss-20b 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-oss-20b
SpecificationOpenAI GPT-4.1 NanoOpenAI gpt-oss-20b
MakerOpenAIOpenAI
WeightsNo public weights listedOpen weights
ReleasedApril 14, 2025August 5, 2025
Context window1.05M131K
Input $/Mtok$0.10$0.03
Output $/Mtok$0.40$0.15
Coding indexNot benchmarkedNot benchmarked
Independent measurements behind it00
Cost per solved taskNot computableNot computable
SourceOpenRouter listingOpenRouter listing

Questions

Is GPT-4.1 Nano better than gpt-oss-20b for coding?

Neither model has a coding score yet, so the two cannot be ranked on coding. Pick GPT-4.1 Nano for a larger context window (1.05M against 131K tokens) and work measured by LiveCodeBench (Vals AI) or LiveCodeBench (Artificial Analysis run), where it leads.

Which is cheaper, GPT-4.1 Nano or gpt-oss-20b?

GPT-4.1 Nano costs $0.10 per million input tokens and $0.40 per million output tokens; gpt-oss-20b costs $0.03 and $0.15. Cost per solved task is known for neither of them.

Which has the bigger context window, GPT-4.1 Nano or gpt-oss-20b?

GPT-4.1 Nano, with 1.05M tokens against 131K.

How many benchmarks is the GPT-4.1 Nano vs gpt-oss-20b comparison based on?

54 benchmarks have a result for both models as of October 23, 2026. GPT-4.1 Nano's coding index rests on 0 independent benchmarks and gpt-oss-20b's on 0. Where only one model has a result, the page says so instead of naming a winner.

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