GLM-4.5 vs GPT-5.5
A complete head-to-head: pricing, context window, benchmarks, modality coverage, and openness, with a programmatic verdict synthesized from the underlying data.
Updated
GLM-4.5 specs · GPT-5.5 specs- PriceTie
Neither model publishes per-token API pricing.
- Context windowGPT-5.5
GPT-5.5 accepts 400K tokens vs 128K, 3.1× the room for long documents and codebases.
- BenchmarksTie
No directly comparable public benchmarks are available for both models, check the spec sheets for individual scores.
- ModalitiesGPT-5.5
GPT-5.5 supports 3 modalities (text, vision, audio) vs 2 for GLM-4.5.
- OpennessGLM-4.5
GLM-4.5 ships open weights (MIT); GPT-5.5 is API-only.
On balance GPT-5.5 edges ahead, winning 2 of 5 categories against GLM-4.5's 1. Neither model publishes per-token API pricing. GPT-5.5 accepts 400K tokens vs 128K, 3.1× the room for long documents and codebases.
No directly comparable public benchmarks are available for both models, check the spec sheets for individual scores. They differ in modality coverage, GLM-4.5 handles text, vision while GPT-5.5 handles text, vision, audio, which can be the deciding factor before you even look at benchmarks. GLM-4.5 ships open weights (MIT); GPT-5.5 is API-only.
GPT-5.5 is the newer of the two, released 7 months after GLM-4.5, which usually means a more recent knowledge cutoff and updated safety post-training. GLM-4.5 is usually picked for chinese llm and open source llm workloads, while GPT-5.5 sees more deployments in agents and tool use. If pricing matters more than every last benchmark point, run the numbers in the calculator below before committing.
Side-by-side specs
| Spec | GLM-4.5 | GPT-5.5 |
|---|---|---|
| Provider | Other | OpenAI |
| Released | Jul 2025 | Mar 2026 |
| Modalities | text, vision | text, vision, audio |
| Context window | 128K tokens | 400K tokens |
| Max output | , | , |
| Input · 1M | Pricing not published | Pricing not published |
| Output · 1M | Pricing not published | Pricing not published |
| Knowledge cutoff | , | , |
| Open weights | Yes (MIT) | No |
| API available | Yes | Yes |
Pricing at scale
What you'd actually pay at typical workloads. Numbers come from each model's published per-million-token rates.
- Light usage, 100k in / 50k out per day, vs ,
- Heavy usage, 1M in / 500k out per day, vs ,
- RAG workload, 5M in / 200k out per day, vs ,
Light usage, 100k in / 50k out per day: pricing not directly comparable (one or both models are missing public per-token rates). Heavy usage, 1M in / 500k out per day: pricing not directly comparable (one or both models are missing public per-token rates). RAG workload, 5M in / 200k out per day: pricing not directly comparable (one or both models are missing public per-token rates).
Estimated spend for the listed models at your usage. Numbers are derived from each model's published per-million-token rates.
- GLM-4.5Pricing unavailable
- GPT-5.5Pricing unavailable
Benchmarks compared
Only sourced numbers. Where a benchmark is missing for one model we show the available value rather than fabricating the other.
GLM-4.5 fits when…
- MIT license
- Strong Chinese
- Multimodal
- Self-hosting and on-prem requirements, open weights (MIT).
GPT-5.5 fits when…
- Industry-leading tool-use and function-calling reliability
- Strong end-to-end agent performance across SWE-bench and GAIA
- Wide ecosystem support, ChatGPT, Realtime API, Responses API
- Long-context tasks, handles 400K tokens vs 128K for GLM-4.5.
- Multimodal needs covering audio.
Consider DBRX
Databricks' 132B MoE, a notable 2024 open-weight release tuned for enterprise.
Frequently asked
Is GLM-4.5 or GPT-5.5 cheaper?
Per-token pricing isn't published for at least one of these models, check each model's spec page for current rates.Which has the larger context window?
GPT-5.5 accepts 400K tokens vs 128K for GLM-4.5.Is GLM-4.5 or GPT-5.5 better for coding?
Both GLM-4.5 and GPT-5.5 are competitive on coding benchmarks. See each model's individual spec page for HumanEval and SWE-bench scores where published. For an opinionated pick, consult our Best LLM for Coding ranking.Are either of these models open source?
GLM-4.5 ships open weights (MIT). GPT-5.5 is API-only.When were GLM-4.5 and GPT-5.5 released?
GLM-4.5 was released by Other on 2025-07-28. GPT-5.5 was released by OpenAI on 2026-03-01.
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