# GPT-5.6 Luna vs Glm 4.5 Air Fp8

On provider list prices, Glm 4.5 Air Fp8 costs $0.20 per million input tokens against $0.20 for GPT-5.6 Luna: effectively level. Output is $1.10 against $1.20 (1.1x).

## Specifications

| | GPT-5.6 Luna | Glm 4.5 Air Fp8 |
| --- | --- | --- |
| Lab | OpenAI | Zai Org |
| Access | API only | Open weights |
| Context window | 1M tokens | 128K tokens |
| List price, input | $0.20 / M tokens | $0.20 / M tokens |
| List price, output | $1.20 / M tokens | $1.10 / M tokens |
| Cached input | $0.02 / M tokens | n/a |
| License | Proprietary API | MIT |
| Fine-tunable | No | Yes |

Specifications and provider list prices from the Allocate catalog, checked 2026-07-21.

## What the numbers say

Take 1,000,000 requests a month at 1,200 input and 350 output tokens each. That workload costs $625 a month on Glm 4.5 Air Fp8 and $660 on GPT-5.6 Luna at list: a gap of $35.

GPT-5.6 Luna reads 1M tokens per request against 128K for Glm 4.5 Air Fp8, 7.6x the window. That decides which one can take whole documents without splitting them.

## Choose GPT-5.6 Luna for

- The longer context window (1M vs 128K tokens)
- Published cached-input pricing ($0.02 per M tokens)

## Choose Glm 4.5 Air Fp8 for

- Open weights you can fine-tune and own
- Fine-tuning under a permissive license (MIT)

## Common questions

### Which is cheaper, GPT-5.6 Luna or Glm 4.5 Air Fp8?

Glm 4.5 Air Fp8, on this workload shape. At list prices it is $0.20/$1.10 per million tokens in and out against $0.20/$1.20 for GPT-5.6 Luna. Billed on Allocate: $0.21/$1.18 against $0.21/$1.28.

### Which has the bigger context window?

GPT-5.6 Luna: 1,000,000 tokens (1M) against 131,072 (128K) for Glm 4.5 Air Fp8.

### Can I fine-tune GPT-5.6 Luna or Glm 4.5 Air Fp8?

Glm 4.5 Air Fp8 publishes open weights (MIT) and can be fine-tuned on your own data. GPT-5.6 Luna is a closed model served over API; its weights are not available.

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[HTML page](https://allocate.network/compare/openai-gpt-5-6-luna-vs-z-ai-glm-4-5-air-fp8) · [GPT-5.6 Luna](https://allocate.network/models/openai-gpt-5-6-luna.md) · [Glm 4.5 Air Fp8](https://allocate.network/models/z-ai-glm-4-5-air-fp8.md) · [Machine-readable catalog](https://allocate.network/catalog.json)