GLM-5.1 vs GPT-5.5
GLM-5.1 (Z.ai (Zhipu AI)) and GPT-5.5 (OpenAI) compared on benchmarks, pricing, context window, and use-case rankings.
- GPT-5.5 leads on overall intelligence (ECI 159 vs 150).
- GLM-5.1 is cheaper on input tokens — $0.98 vs $5.00 per 1M.
- GPT-5.5 has a larger context window (1.1M vs 203K tokens).
- GPT-5.5 ranks higher for coding (89th vs 69th percentile).
Use-case scores are 0–100 percentile composites across each area’s benchmarks, ranked against every model from the past year. Highlighted cells lead each row. Open a model for the full picture.
Frequently asked questions
Is GLM-5.1 better than GPT-5.5?
On Epoch AI's Capabilities Index, GPT-5.5 scores higher (159) than GLM-5.1 (150). The right pick depends on your task — compare their coding, math, and reasoning scores in the table above.
Which is cheaper, GLM-5.1 or GPT-5.5?
GLM-5.1 is cheaper on input tokens at $0.98 per million, versus $5.00 (representative OpenRouter pricing).
Which has a larger context window, GLM-5.1 or GPT-5.5?
GPT-5.5 supports up to 1.1M tokens, compared with 203K for the other.
Which is better for coding, GLM-5.1 or GPT-5.5?
Across coding benchmarks like SWE-bench Verified and Terminal-Bench, GPT-5.5 ranks higher — 89th vs 69th percentile among the models tracked on Model Beat.
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Benchmarks & model data from Epoch AI (CC BY); pricing & specs from OpenRouter. ECI = Epoch Capabilities Index.