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Claude Opus 4.8 vs GLM 5.1

Head to head on 27 shared benchmarks, with price, context window, and release dates.

Benchmark scores

50

evals · sort by any column, ⤢ to expand fullscreen

Model
Claude Opus 4.8

Anthropic

15.5%66.7%67.0%1835elo80.853.9%47.2%92.0%48.7%62.2%80.1%79.3%78.3%67.4%81.4%84.3%89.7%91.8%53.2%85.8%69.0%53.5%75.6%58.3%60.9%82.7%94.4%--80.4%14.5%1281elo40.0%13.4%-22.5%1890elo-56.9%10.4%-69.9%83.4%54.8%--69.2%82.7%-70.9%63.4%
GLM 5.1

Zai

35.9%64.5%40.0%1589elo73.544.8%33.5%83.9%27.9%52.0%72.7%75.4%63.2%68.5%71.8%84.9%72.5%67.0%41.6%72.3%22.2%36.1%71.2%35.6%52.5%31.5%97.1%20.8%1.13-----34.7%--15.1%--85.4%---34.6%5.24--69.8-53.6%
2 / 2 models
AttributeClaude Opus 4.8

Anthropic

GLM 5.1

Zai

DescriptionClaude Opus 4.8 (Adaptive Reasoning, Max Effort) is an AI model from Anthropic.GLM-5.1 is an AI model from Zai, released with open weights.
FamilyClaudeGlm
Params--
Open weights-open
License-mit
Released28 May 20267 Apr 2026
Context1,000,000204,800
Input $/1M$5.00$1.39
Output $/1M$25.00$4.40
Cache read $/1M$0.500$0.234
Cache write $/1M$6.250-
Speed0 tok/s0 tok/s
Latency0.00 s0.00 s
Modalitiestext, image, filetext
Providers--
PublisherAnthropicZai
Reported scores

FAQ

Is Claude Opus 4.8 or GLM 5.1 better?
Across the 27 benchmarks both models report on Sophon, Claude Opus 4.8 leads on 23 of them. Which one is "better" depends on the benchmark - the table above shows every shared score.
How do Claude Opus 4.8 and GLM 5.1 compare on GPQA Diamond?
Claude Opus 4.8 scores 92.0% and GLM 5.1 scores 83.9% on GPQA Diamond.
Which is cheaper, Claude Opus 4.8 or GLM 5.1?
GLM 5.1 is cheaper at $4.40 per million output tokens against $25.00 for Claude Opus 4.8 - about 5.7x.
When were Claude Opus 4.8 and GLM 5.1 released?
Claude Opus 4.8 was released 28 May 2026 by Anthropic. GLM 5.1 was released 7 Apr 2026 by Zai.

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