Noometry

Model comparison

GPT-4.1 nano vs gpt-oss-20b

gpt-oss-20b is the stronger model overall, scoring 32.5 to 27.9 on the Noometry Index.

Last verified . 29 shared benchmarks.

GPT-4.1 nano OpenAI

27.9

Rank #327 Confirmed

gpt-oss-20b OpenAI

32.5

Rank #255 Confirmed

Summary

  • They share 29 benchmarks with published results for both. GPT-4.1 nano scores higher in 3 categories and gpt-oss-20b in 6 categories; 8 gaps are clear of the uncertainty.
  • The widest gap is in agentic & tool use, where GPT-4.1 nano leads 26.5 to 9.3.
  • The biggest single-benchmark swing is OTIS Mock AIME 2024-2025: 28.9% for GPT-4.1 nano and 65.3% for gpt-oss-20b.
  • gpt-oss-20b is cheaper at $0.018 / $0.09 per million input/output tokens, against $0.10 / $0.40 for GPT-4.1 nano.
  • GPT-4.1 nano accepts more context: 1.05M tokens versus 131K.
  • gpt-oss-20b has downloadable open weights; the other is API-only.

Side by side

GPT-4.1 nanogpt-oss-20b
ProviderOpenAIOpenAI
Noometry Index27.932.5
Released2025-04-142025-08-05
WeightsProprietaryOpen
Context window1.05M131K
Max output33K16K
Input $ / M tokens$0.10$0.018
Output $ / M tokens$0.40$0.09
Results tracked3834

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Category by category

Coding gpt-oss-20b leads

GPT-4.1 nano: 24.1 (#330), gpt-oss-20b: 37.6 (#192)

BenchmarkGPT-4.1 nanogpt-oss-20b
SciCode25.9%34.4%
WeirdML19%40.9%
LMArena Coding13061306
Aider Polyglot8.9%—
ALE-Bench—566.05

Agentic & Tool Use GPT-4.1 nano leads

GPT-4.1 nano: 26.5 (#104), gpt-oss-20b: 9.3 (#154)

BenchmarkGPT-4.1 nanogpt-oss-20b
Terminal-Bench—3.4%
Berkeley Function Calling Leaderboard33%—

Reasoning gpt-oss-20b leads

GPT-4.1 nano: 8.5 (#349), gpt-oss-20b: 19.3 (#261)

BenchmarkGPT-4.1 nanogpt-oss-20b
Kagi LLM Benchmark33.3%53.2%
CritPt0%1.4%
LMArena Hard Prompts12861274
DTBench52.5%68%
LMCA5.5%14.5%
Epoch Capabilities Index129.62137.82
ARC-AGI-20%—
ARC-AGI-10%—
Chess Puzzles—4%

Math gpt-oss-20b leads

GPT-4.1 nano: 26.9 (#252), gpt-oss-20b: 39.4 (#103)

BenchmarkGPT-4.1 nanogpt-oss-20b
OTIS Mock AIME 2024-202528.9%65.3%
Omni-MATH36.7%56.5%
LMArena Math12741317
MATH Level 570%—
FrontierMath (Feb 2025 set)1%—

Knowledge gpt-oss-20b leads

GPT-4.1 nano: 21.8 (#273), gpt-oss-20b: 34.6 (#195)

BenchmarkGPT-4.1 nanogpt-oss-20b
GPQA Diamond48.9%60.8%
MMLU-Pro55%74%
GPQA (HELM)50.7%59.4%
LMArena Expert12721258
SimpleQA Verified6%—

Multimodal Not comparable

GPT-4.1 nano: 29.2 (#113), gpt-oss-20b: —

BenchmarkGPT-4.1 nanogpt-oss-20b
LMArena Vision1063—

Multilingual Too close to call

GPT-4.1 nano: 41.6 (#205), gpt-oss-20b: 42.2 (#197)

BenchmarkGPT-4.1 nanogpt-oss-20b
LMArena Non-English12601268
LMArena Chinese12701314
LMArena German12881255
LMArena Japanese11981244
LMArena Russian12611278
LMArena Korean—1236
LMArena Spanish—1267

Instruction Following GPT-4.1 nano leads

GPT-4.1 nano: 67.8 (#193), gpt-oss-20b: 61.8 (#240)

BenchmarkGPT-4.1 nanogpt-oss-20b
IFEval84.3%73.2%
LMArena Instruction Following12671236

Long Context gpt-oss-20b leads

GPT-4.1 nano: 23.7 (#296), gpt-oss-20b: 37.9 (#209)

BenchmarkGPT-4.1 nanogpt-oss-20b
LMArena Longer Query12831250
Fiction.LiveBench25%—

Writing & Preference GPT-4.1 nano leads

GPT-4.1 nano: 40.5 (#243), gpt-oss-20b: 35.5 (#265)

BenchmarkGPT-4.1 nanogpt-oss-20b
LMArena Text12851287
LMArena Creative Writing12601201
EQ-Bench Creative Writing946666
WildBench81.2%73.7%
LMArena Multi-Turn12771268

Frequently asked questions

Is GPT-4.1 nano better than gpt-oss-20b?

gpt-oss-20b is the stronger model overall, scoring 32.5 to 27.9 on the Noometry Index.

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

gpt-oss-20b is cheaper. It lists at $0.018 per million input tokens and $0.09 per million output tokens; GPT-4.1 nano lists at $0.10 and $0.40.

Is GPT-4.1 nano or gpt-oss-20b better for coding?

gpt-oss-20b scores higher on coding benchmarks: 37.6 versus 24.1 in the Noometry coding category.

Which has the bigger context window?

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

How many benchmarks do GPT-4.1 nano and gpt-oss-20b share?

29 benchmarks have published results for both models. GPT-4.1 nano has 38 scored results on Noometry and gpt-oss-20b has 34.

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