Head to head
Z.ai: GLM 5.3 vs OpenAI: GPT-5.6 Luna
Live prices, context windows, capabilities, and measured quality — updated continuously.
Side by side
| Metric | Z.ai: GLM 5.3 Z Ai | OpenAI: GPT-5.6 Luna Openai |
|---|---|---|
| Input $/M tokens | $1.40 | $0.200 |
| Output $/M tokens | $4.40 | $1.20 |
| Context window | 1.0M | 1.1M |
| Max output | 131K | 128K |
| WM Score | 91 | 87 |
| Benchmark quality | 96.3 | 83.7 |
| Hosts serving it | 1 | 3 |
| Throughput (tok/s) | 24 | 108 |
| Latency (ms) | 4957 | 1133 |
| Vision | ||
| Tools | ||
| Reasoning | ||
| JSON mode |
Which should you pick?
OpenAI: GPT-5.6 Luna costs less per million input tokens — about 7.0× cheaper than Z.ai: GLM 5.3. Z.ai: GLM 5.3 scores higher on measured quality. OpenAI: GPT-5.6 Luna takes a larger context window, which matters for long documents or big codebases. Prices here are live list prices; the same model can cost less on a different host, so check the model page for the cheapest offering.