Noometry

Model comparison

Claude Opus 4.6 vs gpt-oss-20b

Claude Opus 4.6 is the stronger model overall, scoring 58.2 to 32.5 on the Noometry Index. gpt-oss-20b costs 278× less per token, which makes it the better buy when Claude Opus 4.6's lead doesn't matter for your workload.

Last verified . 27 shared benchmarks.

Claude Opus 4.6 Anthropic

58.2

Rank #20 Confirmed

gpt-oss-20b OpenAI

32.5

Rank #255 Confirmed

Summary

  • They share 27 benchmarks with published results for both. Claude Opus 4.6 scores higher in 9 categories and gpt-oss-20b in 0 categories; 9 gaps are clear of the uncertainty.
  • The widest gap is in agentic & tool use, where Claude Opus 4.6 leads 51.1 to 9.3.
  • The biggest single-benchmark swing is Terminal-Bench: 79.8% for Claude Opus 4.6 and 3.4% for gpt-oss-20b.
  • gpt-oss-20b is cheaper at $0.018 / $0.09 per million input/output tokens, against $5 / $25 for Claude Opus 4.6.
  • Claude Opus 4.6 accepts more context: 1M tokens versus 131K.
  • gpt-oss-20b has downloadable open weights; the other is API-only.

Side by side

Claude Opus 4.6gpt-oss-20b
ProviderAnthropicOpenAI
Noometry Index58.232.5
Released2026-02-042025-08-05
WeightsProprietaryOpen
Context window1M131K
Max output128K16K
Input $ / M tokens$5$0.018
Output $ / M tokens$25$0.09
Results tracked6834

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Category by category

Coding Claude Opus 4.6 leads

Claude Opus 4.6: 57.2 (#20), gpt-oss-20b: 37.6 (#192)

BenchmarkClaude Opus 4.6gpt-oss-20b
WeirdML78%40.9%
LMArena Coding15361306
ALE-Bench996.5566.05
SWE-bench Verified78.7%—
FrontierCode26.6%—
SWE-bench Verified (bash only)75.6%—
LMArena WebDev1547—
SWE-bench Multilingual72%—
SciCode—34.4%
GSO41.2%—
AlgoTune1.47—

Agentic & Tool Use Claude Opus 4.6 leads

Claude Opus 4.6: 51.1 (#4), gpt-oss-20b: 9.3 (#154)

BenchmarkClaude Opus 4.6gpt-oss-20b
Terminal-Bench79.8%3.4%
APEX-Agents46.3%—
Remote Labor Index4.2%—
τ²-bench Banking27.3%—
Cybench93%—
DeepResearch Bench55.3%—
GBAEval44.1%—
LMArena Search1253—
METR Time Horizons78.9%—
Vending-Bench 28,018—

Reasoning Claude Opus 4.6 leads

Claude Opus 4.6: 57.8 (#23), gpt-oss-20b: 19.3 (#261)

BenchmarkClaude Opus 4.6gpt-oss-20b
Kagi LLM Benchmark83.6%53.2%
Chess Puzzles17%4%
LMArena Hard Prompts15271274
DTBench91.2%68%
LMCA55.8%14.5%
Epoch Capabilities Index155.24137.82
ARC-AGI-269.2%—
SimpleBench67.6%—
NYT Connections (extended)92.1%—
ARC-AGI-194%—
CritPt—1.4%
EnigmaEval7.6%—
Thematic Generalization80.6%—
EBR-Bench12.7%—
Mystery Game Puzzles25%—
ForecastBench60—

Math Claude Opus 4.6 leads

Claude Opus 4.6: 63.0 (#31), gpt-oss-20b: 39.4 (#103)

BenchmarkClaude Opus 4.6gpt-oss-20b
OTIS Mock AIME 2024-202594.4%65.3%
LMArena Math15191317
FrontierMath (Tiers 1-3)66%—
FrontierMath Tier 426.8%—
MathArena Final-Answer Competitions78.5%—
ProofBench50%—
Omni-MATH—56.5%
FrontierMath (Feb 2025 set)40.7%—
FrontierMath Tier 4 (v1)22.9%—

Knowledge Claude Opus 4.6 leads

Claude Opus 4.6: 61.9 (#26), gpt-oss-20b: 34.6 (#195)

BenchmarkClaude Opus 4.6gpt-oss-20b
GPQA Diamond90.5%60.8%
LMArena Expert15461258
Humanity's Last Exam34.4%—
SimpleQA Verified47%—
MMLU-Pro—74%
Vectara Hallucination Rate12.2%—
GPQA (HELM)—59.4%

Multimodal Not comparable

Claude Opus 4.6: 37.3 (#74), gpt-oss-20b: —

BenchmarkClaude Opus 4.6gpt-oss-20b
LMArena Vision1316—
Furniture Assembly28.3%—
LMArena Document1507—

Multilingual Claude Opus 4.6 leads

Claude Opus 4.6: 57.9 (#6), gpt-oss-20b: 42.2 (#197)

BenchmarkClaude Opus 4.6gpt-oss-20b
LMArena Non-English14891268
LMArena Chinese15511314
LMArena German15021255
LMArena Japanese14841244
LMArena Korean14641236
LMArena Russian14971278
LMArena Spanish15101267
LMArena French1513—

Instruction Following Claude Opus 4.6 leads

Claude Opus 4.6: 79.5 (#4), gpt-oss-20b: 61.8 (#240)

BenchmarkClaude Opus 4.6gpt-oss-20b
LMArena Instruction Following15231236
IFEval—73.2%

Long Context Claude Opus 4.6 leads

Claude Opus 4.6: 48.1 (#13), gpt-oss-20b: 37.9 (#209)

BenchmarkClaude Opus 4.6gpt-oss-20b
LMArena Longer Query15201250
CL-bench20.7%—
CL-bench Life17%—

Writing & Preference Claude Opus 4.6 leads

Claude Opus 4.6: 73.5 (#10), gpt-oss-20b: 35.5 (#265)

BenchmarkClaude Opus 4.6gpt-oss-20b
LMArena Text15031287
LMArena Creative Writing15051201
EQ-Bench Creative Writing1809666
LMArena Multi-Turn15131268
WildBench—73.7%
EQ-Bench 41223—

Frequently asked questions

Is Claude Opus 4.6 better than gpt-oss-20b?

Claude Opus 4.6 is the stronger model overall, scoring 58.2 to 32.5 on the Noometry Index. gpt-oss-20b costs 278× less per token, which makes it the better buy when Claude Opus 4.6's lead doesn't matter for your workload.

Which is cheaper, Claude Opus 4.6 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; Claude Opus 4.6 lists at $5 and $25.

Is Claude Opus 4.6 or gpt-oss-20b better for coding?

Claude Opus 4.6 scores higher on coding benchmarks: 57.2 versus 37.6 in the Noometry coding category.

Which has the bigger context window?

Claude Opus 4.6 does, with 1M tokens against 131K.

How many benchmarks do Claude Opus 4.6 and gpt-oss-20b share?

27 benchmarks have published results for both models. Claude Opus 4.6 has 68 scored results on Noometry and gpt-oss-20b has 34.

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