GLM-5.3 vs GPT-5.6 Luna: Specs & Benchmark Comparison
GLM-5.3 is developed by Zhipu AI, while GPT-5.6 Luna comes from OpenAI. GPT-5.6 Luna was released in July 2026, and GLM-5.3 followed a month later in August 2026. GLM-5.3 has a published size of about 753 billion parameters; OpenAI has not disclosed the parameter count of GPT-5.6 Luna.
The two models share 8 published benchmarks. GLM-5.3 leads on 6 of them, GPT-5.6 Luna on 2. The widest gaps are on AutomationBench, where GLM-5.3 scores 48.2% against 14.9%; Terminal-Bench 4.0, where GLM-5.3 scores 41.8% against 17.3%. Averaged across everything we track, GLM-5.3 sits at 52.2% and GPT-5.6 Luna at 51.5%.
GPT-5.6 Luna is the cheaper API at $0.20 per million input tokens and $1.20 per million output tokens, roughly 7 times cheaper than GLM-5.3 at $1.40 and $4.40. Both accept a context window of about 1M tokens. GLM-5.3 accepts text as input, while GPT-5.6 Luna accepts text and images.
| Characteristic | GLM-5.3 | GPT-5.6 Luna |
|---|---|---|
| Company | Zhipu AI | OpenAI |
| Release Date | August 14, 2026 | July 9, 2026 |
| Parameters | 753B | — |
| Multimodal | No | Yes |
| Context (input) | 1.0M | 1.1M |
| Context (output) | 131K | 128K |
| Input Price / 1M | $1.40 | $0.20 |
| Output Price / 1M | $4.40 | $1.20 |
| Average Score | 52.2% | 51.5% |
| Benchmarks | ||
| AutomationBench | 48.2% | 14.9% |
| Terminal-Bench 4.0 | 41.8% | 17.3% |
| Agents' Last Exam | 28.5% | 50.3% |
| ExploitBench | 54.4% | 33.2% |
| Toolathlon | 73.0% | 53.4% |
| Terminal-Bench 2.1 | 88.0% | 84.7% |
| ExploitGym | 15.0% | 12.4% |
| DeepSWE 1.1 | 66.9% | 67.0% |
Visual Benchmark Comparison
Verdict
GPT-5.6 Luna leads in 2 out of 4 comparison categories.
Both models show comparable average scores: GLM-5.3 — 0.5, GPT-5.6 Luna — 0.5.
GPT-5.6 Luna is 4.1x cheaper: input $0.20/1M vs $1.40/1M tokens.
GPT-5.6 Luna supports a larger context: 1M vs 1M tokens.
GLM-5.3 is newer: released 8/14/2026 vs 7/9/2026.
More About These Models
Frequently Asked Questions
Which is better for coding — GLM-5.3 or GPT-5.6 Luna?
Which model is cheaper — GLM-5.3 or GPT-5.6 Luna?
Which has a larger context window — GLM-5.3 or GPT-5.6 Luna?
The GLM-5.3 and GPT-5.6 Luna comparison is updated for 2026. Data includes benchmark results, API pricing, context window size and other specifications. For more detailed information, visit the GLM-5.3 or GPT-5.6 Luna page. See also the complete list of AI model comparisons.