GPT-5.6 Terra vs GLM-5.2
OpenAI's GPT-5.6 Terra and Z.ai's GLM-5.2 both target production language workloads, but they price and behave differently. Here is the side-by-side.
Pricing checked against provider documentation on . How we verify
The short answer
GLM-5.2 is the cheaper option — roughly 2.1x less on a blended workload, and it suits mit-licensed coding agents. GPT-5.6 Terra justifies its premium when you need balanced production workloads.
OpenAI • GPT-5.6
$2.00 / $12.00
/ 1M tokens (input / output)
The everyday tier of the GPT-5.6 family, roughly corresponding to the old 'mini' slot but benchmarking above the previous generation's flagship. For most application backends this is the default worth trying before reaching for Sol, since it clears Claude Fable 5 on several evals at a fraction of the cost.
Z.ai • GLM-5
$1.40 / $4.40
/ 1M tokens (input / output)
A 744B-parameter MoE with 40B active, MIT-licensed, and tuned for long-horizon coding work. It sits between DeepSeek and Kimi on price and is the usual challenger when a cheaper model keeps looping or missing repository conventions — enough capability to finish the task without flagship pricing.
Input price
GLM-5.2 is 30% cheaper than GPT-5.6 Terra on input tokens.
Output price
GLM-5.2 is 63% cheaper than GPT-5.6 Terra on output tokens — usually the side that dominates the bill.
Monthly cost at three workload sizes
Standard (non-batch, non-cached) rates. Reasoning models will exceed these figures because thinking tokens bill as output.
| Workload | GPT-5.6 Terra | GLM-5.2 | Difference |
|---|---|---|---|
| Light — 1M in / 200K out | $4 | $2 | $2 |
| Moderate — 10M in / 2M out | $44 | $23 | $21 |
| Heavy — 100M in / 20M out | $440 | $228 | $212 |
Specification comparison
| Attribute | GPT-5.6 Terra | GLM-5.2 |
|---|---|---|
| Input (/ 1M tokens) | $2.00 | $1.40 |
| Output (/ 1M tokens) | $12.00 | $4.40 |
| Cached input | $0.20 | $0.26 |
| Context window | 1,048,576 tokens | 1,000,000 tokens |
| Max output | 128,000 tokens | 131,072 tokens |
| Native reasoning | Yes | Yes |
| Knowledge cutoff | 2026-02 | 2026-02 |
| Relative latency | medium | medium |
| Open weights | No | MIT |
| API model ID | gpt-5.6-terra | glm-5.2 |
| Status | stable | stable |
GPT-5.6 Terra: Cut 20% from the $2.50/$15 launch price on 2026-07-30.
GLM-5.2: Independently measured by Artificial Analysis; the vendor's own pricing page was unreachable at time of checking. Treat as approximate and confirm in the console.
Choose GPT-5.6 Terra if…
- Customer support and chat backends
- RAG and document processing pipelines
- Mid-complexity coding tasks
- Tool-calling agents at scale
Choose GLM-5.2 if…
- Coding agents on large repositories
- Long-horizon refactors
- Self-hosted agent stacks
- Structured output pipelines
Frequently asked
Is GPT-5.6 Terra or GLM-5.2 cheaper?
GLM-5.2 is cheaper. On a blended 3:1 input-to-output workload it costs about 2.1x less than GPT-5.6 Terra.
Which has the larger context window, GPT-5.6 Terra or GLM-5.2?
GPT-5.6 Terra has the larger window at 1.05M tokens versus 1M.
Should I use GPT-5.6 Terra or GLM-5.2?
Pick GPT-5.6 Terra for balanced production workloads. Pick GLM-5.2 for mit-licensed coding agents. If cost dominates the decision, GLM-5.2 wins; if you need the capability ceiling, benchmark both on your own evals before committing.