GLM-4.6 vs GPT-5.5
Benchmarks, API pricing and specs, head to head. Data updated 2026-06-10.
Z.ai (Zhipu) · Sep 2025
The budget coding-agent favorite of late 2025 — near-Sonnet coding utility with MIT weights and a $3/month plan.
OpenAI · Apr 2026
OpenAI's flagship reasoning model with a 1M-token context window, built for hard coding, science and long-horizon agentic work.
The verdict
GPT-5.5 wins 4 of the 4 benchmarks these models share, against 0 for GLM-4.6. On price the gap is dramatic: GLM-4.6 works out roughly 11x cheaper per blended million tokens. GPT-5.5 also takes 1M of context versus 200K for GLM-4.6. And GLM-4.6 is open-weights (MIT), so it can be self-hosted — a structural advantage if data control or vendor independence matters.
Benchmark head-to-head 0–4
Specs & pricing
| GLM-4.6 | GPT-5.5 | |
|---|---|---|
| modhub Index | 63.9 | 77.2 |
| Input price / 1M | $0.6 | $5 |
| Output price / 1M | $2.2 | $30 |
| Context window | 200K | 1M |
| Max output | 128K | 128K |
| Open weights | yes (MIT) | no |
| Reasoning model | yes | yes |
| Multimodal input | text | text, image |
| Knowledge cutoff | Jul 2025 | Jan 2026 |
| Released | Sep 2025 | Apr 2026 |
| Example monthly cost* | $9.30 | $95.00 |
* 10M input + 1.5M output tokens per month at list prices, no caching. Green = better value on that row.
Frequently asked questions
- Which is better, GLM-4.6 or GPT-5.5?
- GPT-5.5 wins 4 of the 4 benchmarks these models share, against 0 for GLM-4.6. On price the gap is dramatic: GLM-4.6 works out roughly 11x cheaper per blended million tokens. GPT-5.5 also takes 1M of context versus 200K for GLM-4.6. And GLM-4.6 is open-weights (MIT), so it can be self-hosted — a structural advantage if data control or vendor independence matters.
- Which is cheaper, GLM-4.6 or GPT-5.5?
- GLM-4.6 costs $0.6/$2.2 per million input/output tokens, while GPT-5.5 costs $5/$30. For a typical workload of 10M input and 1.5M output tokens per month, that's $9.30 versus $95.00.
- Which model is better for coding, GLM-4.6 or GPT-5.5?
- On SWE-bench Verified — the standard agentic-coding benchmark — GPT-5.5 scores 82.6% versus 68% for GLM-4.6, making GPT-5.5 the stronger pick for coding agents.