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Claude Opus 4.1 vs gpt-oss-120b

Claude Opus 4.1 leads gpt-oss-120b on the Artificial Analysis Intelligence Index, 22.8 to 11.6, and gpt-oss-120b costs 150.0x less per output token ($0.50 vs $75.00 per million). Updated October 22, 2026; 56 benchmarks have a result for both.

Replace Claude Opus 4.1 Replace gpt-oss-120b
Claude Opus 4.1Anthropic
Coding
No data
Overall
50.2
Output $/M
$75.00
50
gpt-oss-120bOpenAI
Coding
No data
Overall
50.0
Output $/M
$0.50
6
vs boards won of 56 shared

Claude Opus 4.1 or gpt-oss-120b: which to pick

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

Pick Claude Opus 4.1 for a larger context window (200K against 131K tokens) and work measured by LiveCodeBench (Vals AI) or WeirdML, where it leads.

Model AClaude Opus 4.1AnthropicNot benchmarked1 independent benchmarkNo cost per solved taskModel Bgpt-oss-120bOpenAINot benchmarked1 independent benchmark$0.51 per solved task
Shared results
56
Claude Opus 4.1 only
17
gpt-oss-120b only
25
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
Claude Opus 4.1 not benchmarked, gpt-oss-120b not benchmarked.
Widest category
Web design, 26.3 points apart on average over 6 shared benchmarks.
Widest single gap
SimpleBench: Claude Opus 4.1 60.0% against gpt-oss-120b 22.1%, 37.9 points apart on a 0 to 100 scale.
Output price
Claude Opus 4.1 $75.00 against gpt-oss-120b $0.50 per million output tokens, 150.0x apart.
Context window
Claude Opus 4.1 takes 200K tokens, gpt-oss-120b 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
CategoryClaude Opus 4.1Barsgpt-oss-120bTies
Coding33
Intelligence20
Agentic work10
Reasoning61
Math42
Knowledge80
Web design60
General200
All shared boards506
CodingLike-for-likeSix of these boards feed the Vibe Coding Index33
Coding benchmarks for Claude Opus 4.1 and gpt-oss-120b
BenchmarkClaude Opus 4.1gpt-oss-120bLeader
Aider polyglotNot measured41.8%Only gpt-oss-120b measured
SWE-bench VerifiedNot measured26.0%Only gpt-oss-120b measured
LMArena WebDev1390Not measuredOnly Claude Opus 4.1 measured
AA Coding IndexNot measured30.4Only gpt-oss-120b measured
LiveCodeBench (Vals AI)66.5%83.2%gpt-oss-120b
SWE-bench Verified (Vals AI)Not measured33.6%Only gpt-oss-120b measured
LiveCodeBench (Artificial Analysis run)Not measured87.8%Only gpt-oss-120b measured
SciCodeNot measured34.0%Only gpt-oss-120b measured
Terminal-Bench Hard (Artificial Analysis run)Not measured23.5%Only gpt-oss-120b measured
Terminal-Bench38.0%18.7%Claude Opus 4.1
WeirdML45.9%48.2%gpt-oss-120b
Cybench42.0%Not measuredOnly Claude Opus 4.1 measured
ALE-BenchNot measured575.6Only gpt-oss-120b measured
LMArena Text: coding14791379Claude Opus 4.1
LMArena Text: software and IT14561387Claude Opus 4.1
LMArena WebDev: HTML1399Not measuredOnly Claude Opus 4.1 measured
SciCode4.6%7.7%gpt-oss-120b
Neither model has a result on the other 22 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index20
Intelligence benchmarks for Claude Opus 4.1 and gpt-oss-120b
BenchmarkClaude Opus 4.1gpt-oss-120bLeader
AA Intelligence Index22.811.6Claude Opus 4.1
Epoch Capabilities Index144.1139.8Claude Opus 4.1
Agentic workLike-for-likePublic boards, shown as published, kept out of the index10
Agentic work benchmarks for Claude Opus 4.1 and gpt-oss-120b
BenchmarkClaude Opus 4.1gpt-oss-120bLeader
AA Agentic IndexNot measured3.7Only gpt-oss-120b measured
τ²-Bench TelecomNot measured65.8%Only gpt-oss-120b measured
APEX-AgentsNot measured4.4%Only gpt-oss-120b measured
METR time horizons66.8%56.6%Claude Opus 4.1
GDPval43.6%Not measuredOnly Claude Opus 4.1 measured
DeepResearch Bench48.3%Not measuredOnly Claude Opus 4.1 measured
Vending-Bench 2Not measured-$22Only gpt-oss-120b measured
BrowseComp-PlusNot measured67.0%Only gpt-oss-120b measured
Neither model has a result on the other 33 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index61
Reasoning benchmarks for Claude Opus 4.1 and gpt-oss-120b
BenchmarkClaude Opus 4.1gpt-oss-120bLeader
GPQA Diamond76.3%78.5%gpt-oss-120b
MMMU Pro (Vals AI)77.5%Not measuredOnly Claude Opus 4.1 measured
GPQA Diamond (Artificial Analysis run)Not measured78.2%Only gpt-oss-120b measured
Humanity's Last Exam (Artificial Analysis run)Not measured19.6%Only gpt-oss-120b measured
GPQA Diamond (Epoch AI run)77.3%75.8%Claude Opus 4.1
SimpleBench60.0%22.1%Claude Opus 4.1
Mystery game puzzles21.0%2.0%Claude Opus 4.1
EBR-bench7.9%Not measuredOnly Claude Opus 4.1 measured
VPCT35.0%Not measuredOnly Claude Opus 4.1 measured
LMArena Text: hard prompts14421364Claude Opus 4.1
LMArena Text: expert14381356Claude Opus 4.1
LMArena Text: hard prompts in English14511368Claude Opus 4.1
Kagi LLM BenchmarkNot measured58.6%Only gpt-oss-120b measured
Neither model has a result on the other 9 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index42
Math benchmarks for Claude Opus 4.1 and gpt-oss-120b
BenchmarkClaude Opus 4.1gpt-oss-120bLeader
AIME78.2%92.6%gpt-oss-120b
MATH 500 (Vals AI)95.4%94.8%Claude Opus 4.1
MGSM (Vals AI)94.4%92.0%Claude Opus 4.1
AA Math IndexNot measured93.4Only gpt-oss-120b measured
AIME 2025 (Artificial Analysis run)Not measured93.4%Only gpt-oss-120b measured
OTIS Mock AIME68.9%88.9%gpt-oss-120b
FrontierMath, tiers 1 to 312.6%Not measuredOnly Claude Opus 4.1 measured
FrontierMath, tier 42.4%Not measuredOnly Claude Opus 4.1 measured
LMArena Text: math14311389Claude Opus 4.1
LMArena Text: mathematical work14341386Claude Opus 4.1
Neither model has a result on the other 3 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index80
Knowledge benchmarks for Claude Opus 4.1 and gpt-oss-120b
BenchmarkClaude Opus 4.1gpt-oss-120bLeader
MMLU Pro87.9%79.2%Claude Opus 4.1
LegalBench (Vals AI)83.5%75.9%Claude Opus 4.1
CaseLaw (Vals AI)Not measured48.8%Only gpt-oss-120b measured
CorpFin (Vals AI)Not measured58.2%Only gpt-oss-120b measured
TaxEval (Vals AI)73.7%71.6%Claude Opus 4.1
MortgageTax (Vals AI)61.1%Not measuredOnly Claude Opus 4.1 measured
MedQA (Vals AI)93.6%91.4%Claude Opus 4.1
MedCode (Vals AI)47.2%Not measuredOnly Claude Opus 4.1 measured
MMLU Pro (Artificial Analysis run)Not measured80.8%Only gpt-oss-120b measured
LMArena Text: science14221382Claude Opus 4.1
LMArena Text: medicine and healthcare14161388Claude Opus 4.1
LMArena Text: legal and government14211355Claude Opus 4.1
LMArena Text: business and finance14061359Claude Opus 4.1
FACTS Benchmark Suite40.4%Not measuredOnly Claude Opus 4.1 measured
Neither model has a result on the other 4 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index60
Web design benchmarks for Claude Opus 4.1 and gpt-oss-120b
BenchmarkClaude Opus 4.1gpt-oss-120bLeader
Design Arena: websites1176967Claude Opus 4.1
Design Arena: UI components1162924Claude Opus 4.1
Design Arena: game dev1171992Claude Opus 4.1
Design Arena: data viz1166987Claude Opus 4.1
Design Arena: 3D1152901Claude Opus 4.1
Design Arena: all code categories1170962Claude Opus 4.1
Design Arena: SVG1152Not measuredOnly Claude Opus 4.1 measured
Design Arena: ASCII art1167Not measuredOnly Claude Opus 4.1 measured
Neither model has a result on the other 1 board here
GeneralLike-for-likePublic boards, shown as published, kept out of the index200
General benchmarks for Claude Opus 4.1 and gpt-oss-120b
BenchmarkClaude Opus 4.1gpt-oss-120bLeader
SAGE (Vals AI)31.4%Not measuredOnly Claude Opus 4.1 measured
MedScribe (Vals AI)73.9%Not measuredOnly Claude Opus 4.1 measured
IFBenchNot measured69.0%Only gpt-oss-120b measured
Long context reasoning (AA-LCR)Not measured52.0%Only gpt-oss-120b measured
DTBench80.0%76.3%Claude Opus 4.1
LMCA37.1%22.1%Claude Opus 4.1
Fiction.LiveBenchNot measured44.4%Only gpt-oss-120b measured
Creative writing (Lech Mazur)84.7%77.1%Claude Opus 4.1
Surface Evolver BenchNot measured25.0%Only gpt-oss-120b measured
LMArena Text14191366Claude Opus 4.1
LMArena Text: instruction following14351318Claude Opus 4.1
LMArena Text: creative writing14121274Claude Opus 4.1
LMArena Text: English14331375Claude Opus 4.1
LMArena Text: non-English14051351Claude Opus 4.1
LMArena Text: Chinese14271385Claude Opus 4.1
LMArena Text: German14131353Claude Opus 4.1
LMArena Text: Japanese13771331Claude Opus 4.1
LMArena Text: Korean13811282Claude Opus 4.1
LMArena Text: French14331370Claude Opus 4.1
LMArena Text: Spanish14481389Claude Opus 4.1
LMArena Text: Russian14221343Claude Opus 4.1
LMArena Text: Polish14131353Claude Opus 4.1
LMArena Text: multi-turn14441340Claude Opus 4.1
LMArena Text: longer queries14551319Claude Opus 4.1
LMArena Text: writing and language14181306Claude Opus 4.1
LMArena Text: entertainment and media13981292Claude Opus 4.1
Neither model has a result on the other 20 boards here
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
Image generation benchmarks for Claude Opus 4.1 and gpt-oss-120b
BenchmarkClaude Opus 4.1gpt-oss-120bLeader
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

Claude Opus 4.1$0.052Fits in one request
gpt-oss-120b$0.0003Fits in one request

gpt-oss-120b costs less

Repository review

50K input + 3K output tokens

Claude Opus 4.1$0.975Fits in one request
gpt-oss-120b$0.0065Fits in one request

gpt-oss-120b costs less

Agent loop

200K input + 10K output tokens

Claude Opus 4.1$3.75Exceeds the context window
gpt-oss-120b$0.025Exceeds the context window

gpt-oss-120b 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 Claude Opus 4.1 and gpt-oss-120b
SpecificationAnthropic Claude Opus 4.1OpenAI gpt-oss-120b
MakerAnthropicOpenAI
WeightsNo public weights listedOpen weights
ReleasedAugust 5, 2025August 5, 2025
Context window200K131K
Input $/Mtok$15.00$0.10
Output $/Mtok$75.00$0.50
Coding indexNot benchmarkedNot benchmarked
Independent measurements behind it11
Cost per solved taskNot computable$0.51
SourceOpenRouter listingOpenRouter listing

Questions

Is Claude Opus 4.1 better than gpt-oss-120b for coding?

Neither model has a coding score yet, so the two cannot be ranked on coding. Pick Claude Opus 4.1 for a larger context window (200K against 131K tokens) and work measured by LiveCodeBench (Vals AI) or WeirdML, where it leads.

Which is cheaper, Claude Opus 4.1 or gpt-oss-120b?

Claude Opus 4.1 costs $15.00 per million input tokens and $75.00 per million output tokens; gpt-oss-120b costs $0.10 and $0.50. Cost per solved task is known for gpt-oss-120b only.

Which has the bigger context window, Claude Opus 4.1 or gpt-oss-120b?

Claude Opus 4.1, with 200K tokens against 131K.

How many benchmarks is the Claude Opus 4.1 vs gpt-oss-120b comparison based on?

56 benchmarks have a result for both models as of October 22, 2026. Claude Opus 4.1's coding index rests on 1 independent benchmark and gpt-oss-120b's on 1. Where only one model has a result, the page says so instead of naming a winner.

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