Model comparison

gpt-oss-20b vs Kimi K3

Kimi K3 is the stronger model overall, scoring 59.5 to 32.5 on the Noometry Index. gpt-oss-20b costs 167× less per token, which makes it the better buy when Kimi K3's lead doesn't matter for your workload.

Last verified . 27 shared benchmarks.

gpt-oss-20b OpenAI

32.5

Rank #255 Confirmed

Kimi K3 Moonshot AI

59.5

Rank #15 Confirmed

Summary

  • They share 27 benchmarks with published results for both. gpt-oss-20b scores higher in 0 categories and Kimi K3 in 9 categories; 9 gaps are clear of the uncertainty.
  • The widest gap is in reasoning, where Kimi K3 leads 63.0 to 19.3.
  • The biggest single-benchmark swing is WeirdML: 40.9% for gpt-oss-20b and 82.6% for Kimi K3.
  • gpt-oss-20b is cheaper at $0.018 / $0.09 per million input/output tokens, against $3 / $15 for Kimi K3.
  • Kimi K3 accepts more context: 1.05M tokens versus 131K.

Side by side

gpt-oss-20b and Kimi K3 specifications
gpt-oss-20bKimi K3
ProviderOpenAIMoonshot AI
Noometry Index32.559.5
Released2025-08-052026-07-16
WeightsOpenOpen
Context window131K1.05M
Max output16K1.05M
Input $ / M tokens$0.018$3
Output $ / M tokens$0.09$15
Results tracked3453

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Category by category

Coding Kimi K3 leads

gpt-oss-20b: 37.6 (#192), Kimi K3: 61.0 (#10)

Coding benchmarks
Benchmarkgpt-oss-20bKimi K3
SciCode34.4%59.5%
WeirdML40.9%82.6%
LMArena Coding13061508
ALE-Bench566.051,524
DeepSWE—68.5%
FrontierCode—44.2%
LMArena WebDev—1654
FrontierSWE—25.9%

Agentic & Tool Use Kimi K3 leads

gpt-oss-20b: 9.3 (#154), Kimi K3: 41.8 (#20)

Agentic & Tool Use benchmarks
Benchmarkgpt-oss-20bKimi K3
Terminal-Bench3.4%—
APEX-Agents—50.6%
τ²-bench Banking—37.1%
PostTrainBench—32%
GBAEval—48.3%
GDP.pdf—19%
Vending-Bench 2—5,165

Reasoning Kimi K3 leads

gpt-oss-20b: 19.3 (#261), Kimi K3: 63.0 (#17)

Reasoning benchmarks
Benchmarkgpt-oss-20bKimi K3
CritPt1.4%23.4%
Chess Puzzles4%39%
LMArena Hard Prompts12741496
DTBench68%91.2%
LMCA14.5%52.7%
Epoch Capabilities Index137.82157.45
ARC-AGI-2—60.4%
SimpleBench—60.7%
Kagi LLM Benchmark53.2%—
NYT Connections (extended)—93.6%
ARC-AGI-1—94.5%
Mystery Game Puzzles—26%
Surface Evolver Bench—95%
ForecastBench—61.1

Math Kimi K3 leads

gpt-oss-20b: 39.4 (#103), Kimi K3: 74.2 (#16)

Math benchmarks
Benchmarkgpt-oss-20bKimi K3
OTIS Mock AIME 2024-202565.3%97.2%
LMArena Math13171491
FrontierMath (Tiers 1-3)—72.2%
FrontierMath Tier 4—39%
MathArena Final-Answer Competitions—87.8%
ProofBench—87%
Omni-MATH56.5%—

Knowledge Kimi K3 leads

gpt-oss-20b: 34.6 (#195), Kimi K3: 63.2 (#21)

Knowledge benchmarks
Benchmarkgpt-oss-20bKimi K3
GPQA Diamond60.8%93.1%
LMArena Expert12581521
SimpleQA Verified—50.6%
MMLU-Pro74%—
GPQA (HELM)59.4%—

Multimodal Not comparable

gpt-oss-20b: —, Kimi K3: 37.8 (#70)

Multimodal benchmarks
Benchmarkgpt-oss-20bKimi K3
Blueprint-Bench 2—29.5%
Furniture Assembly—34.2%

Multilingual Kimi K3 leads

gpt-oss-20b: 42.2 (#197), Kimi K3: 56.3 (#21)

Multilingual benchmarks
Benchmarkgpt-oss-20bKimi K3
LMArena Non-English12681466
LMArena Chinese13141529
LMArena German12551488
LMArena Japanese12441487
LMArena Korean12361458
LMArena Russian12781482
LMArena Spanish12671472
LMArena French—1491

Instruction Following Kimi K3 leads

gpt-oss-20b: 61.8 (#240), Kimi K3: 77.7 (#14)

Instruction Following benchmarks
Benchmarkgpt-oss-20bKimi K3
LMArena Instruction Following12361483
IFEval73.2%—

Long Context Kimi K3 leads

gpt-oss-20b: 37.9 (#209), Kimi K3: 45.8 (#29)

Long Context benchmarks
Benchmarkgpt-oss-20bKimi K3
LMArena Longer Query12501494

Writing & Preference Kimi K3 leads

gpt-oss-20b: 35.5 (#265), Kimi K3: 76.6 (#4)

Writing & Preference benchmarks
Benchmarkgpt-oss-20bKimi K3
LMArena Text12871476
LMArena Creative Writing12011454
EQ-Bench Creative Writing6662082
LMArena Multi-Turn12681488
WildBench73.7%—
EQ-Bench 4—1339

Frequently asked questions

Is gpt-oss-20b better than Kimi K3?

Kimi K3 is the stronger model overall, scoring 59.5 to 32.5 on the Noometry Index. gpt-oss-20b costs 167× less per token, which makes it the better buy when Kimi K3's lead doesn't matter for your workload.

Which is cheaper, gpt-oss-20b or Kimi K3?

gpt-oss-20b is cheaper. It lists at $0.018 per million input tokens and $0.09 per million output tokens; Kimi K3 lists at $3 and $15.

Is gpt-oss-20b or Kimi K3 better for coding?

Kimi K3 scores higher on coding benchmarks: 61.0 versus 37.6 in the Noometry coding category.

Which has the bigger context window?

Kimi K3 does, with 1.05M tokens against 131K.

How many benchmarks do gpt-oss-20b and Kimi K3 share?

27 benchmarks have published results for both models. gpt-oss-20b has 34 scored results on Noometry and Kimi K3 has 53.

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