The Known Good Updated 4 Sep 2026 Subscribe
Anthropic: Claude Opus 4.6 vs OpenAI: gpt-oss-120b ·Anthropic vs OpenAI

Anthropic: Claude Opus 4.6 vs OpenAI: gpt-oss-120b — head-to-head comparison

Anthropic: Claude Opus 4.6 profile OpenAI: gpt-oss-120b profile All comparisons
Anthropic: Claude Opus 4.6 — Anthropic
Quality
#13 of 65
89based on 5 of 7 evaluations
Known Good Index
Speed
#238 of 338
35.1
Output tokens per second
Price
#411 of 442
$10.00
Blended per 1M tokens
In $5.00 · Out $25.00
Cache hit price
#298 of 324
$0.50
per 1M tokens (−90%)
Context
#151 of 476
1.00M
tokens (~1,500 pages)
OpenAI: gpt-oss-120b — OpenAI
Quality
#44 of 65
62based on 3 of 7 evaluations
Known Good Index
Speed
#9 of 338
166.7
Output tokens per second
Price
#19 of 442
$0.07
Blended per 1M tokens
In $0.04 · Out $0.17
Cache hit price
unranked
per 1M tokens
Context
#363 of 476
131k
tokens (~200 pages)
Summary

On the Known Good Index, Anthropic: Claude Opus 4.6 scores 89 and OpenAI: gpt-oss-120b scores 62 — a 27-point lead for Anthropic: Claude Opus 4.6. They share 3 published evaluations, with Anthropic: Claude Opus 4.6 ahead on 3 and OpenAI: gpt-oss-120b ahead on 0.

Blended pricing is $10.00 per 1M tokens for Anthropic: Claude Opus 4.6 and $0.07 for OpenAI: gpt-oss-120b — OpenAI: gpt-oss-120b is about 142.3× cheaper.

Throughput is 35 tokens per second for Anthropic: Claude Opus 4.6 and 167 for OpenAI: gpt-oss-120b, with time to first token at 2.0s and 0.6s. Anthropic: Claude Opus 4.6 accepts 1.00M tokens of context against 131k.

Anthropic: Claude Opus 4.6 is proprietary; OpenAI: gpt-oss-120b is open weights under Open weights (unrestricted). 21 tracked hosts serve one or both, and 2 serve both.

Generated from tracked data on 4 Sep 2026 · how these comparisons are computed →

At a glance
MetricAnthropic: Claude Opus 4.6OpenAI: gpt-oss-120b
Known Good Index 89 based on 5 of 7 evaluations 62 based on 3 of 7 evaluations
Blended $/1M $10.00 $0.07
Output tok/s 35 167
Context window 1.00M 131k
Providers 5 18
Jump to section

Quality

Known Good Index and the capability indices, side by side

Index scores

Each index is min-max normalised across tracked models and scaled 0–100 from published evaluations. We do not run these evaluations.

MetricAnthropic: Claude Opus 4.6OpenAI: gpt-oss-120b
Known Good Index 89 62
Coding Index 92
Reasoning Index 83
Openness Index 5 60
The Known Good

Quality Breakdown

Every evaluation both models report a published score for

Evaluations both models report

Bar = Anthropic: Claude Opus 4.6 · marker = OpenAI: gpt-oss-120b · scores ingested from Epoch AI (CC-BY 4.0)

GPQA Diamond91 / 76
Mock AIME 2024–2593 / 89
Terminal-Bench80 / 19

Right-hand figures read Anthropic: Claude Opus 4.6 / OpenAI: gpt-oss-120b. Anthropic: Claude Opus 4.6 leads on 3 of 3, OpenAI: gpt-oss-120b on 0.

The Known Good

Arena Elo

Human preference rating from blind pairwise votes

Arena ratings

Elo from blind pairwise votes, ingested from Arena. Higher is better.

MetricAnthropic: Claude Opus 4.6OpenAI: gpt-oss-120b
Text Arena 1,498 1,366
Text Arena (style controlled) 1,498 1,352
The Known Good

Price & Cost

Published API pricing by token type

Published pricing

USD per 1M tokens. Blended is a 3:1 input:output mix. Live from OpenRouter, cross-checked against models.dev. Lower is better.

MetricAnthropic: Claude Opus 4.6OpenAI: gpt-oss-120b
Input $/1M $5.00 $0.04
Output $/1M $25.00 $0.17
Blended $/1M $10.00 $0.07
Cache read $/1M $0.500
The Known Good
We publish blended price rather than cost-per-task. Cost-per-task requires token counts from an evaluation suite we do not run. Blended price is computed from published rates and is fully reproducible — see the pricing methodology.

Context Window

Maximum input accepted and maximum output emitted

Context and output limits

Provider-declared limits, from metadata via models.dev and OpenRouter. Higher is better.

MetricAnthropic: Claude Opus 4.6OpenAI: gpt-oss-120b
Context window 1.00M 131k
Max output tokens 128k 118k
The Known Good

Speed & Latency

Mean throughput and time to first token across hosting providers, over successful measurements from the last 48 hours

Throughput and latency

Means across all tracked providers over successful measurements from the last 48 hours, derived from OpenRouter endpoint telemetry.

MetricAnthropic: Claude Opus 4.6OpenAI: gpt-oss-120b
Output tokens/s 35 167
Time to first token 2.0s 0.6s
The Known Good

Providers

Which hosts serve each model, and at what price and speed

21 hosts · 2 serve both
Full provider benchmarks →
Provider Anthropic: Claude Opus 4.6 blendedAnthropic: Claude Opus 4.6 tok/s OpenAI: gpt-oss-120b blendedOpenAI: gpt-oss-120b tok/s
Google · first party $10.00 45 $0.16 142
Claude Platform on AWS $10.00 42
Amazon Bedrock · first party $10.00 38 $0.26 330
Azure · first party $10.00 34
Anthropic · first party $10.00 32
Cerebras $0.45 788
Groq $0.26 344
SambaNova $0.34 319
Nebius $0.26 247
BaseTen $0.20 187
Mara $0.30 150
DeepInfra $0.07 130
Parasail $0.26 107
Novita $0.10 102
Mancer 2 $0.17 95
Phala $0.26 85
Together $0.26 60
CoreWeave $0.07 57
AkashML $0.07 43
DigitalOcean $0.14 27
SiliconFlow $0.15 18

Per-host pricing and telemetry from OpenRouter. A dash means that host does not serve that model.

The Known Good
Sources for this page
Pricing & providers — OpenRouter Metadata — models.dev Benchmarks — Epoch AI (CC-BY 4.0)Elo — Arena Full attribution →