GPT-5.6 Terra Pro is $0.8 cheaper per 1M input tokens (28.6% lower; 1.4x difference).
API cost decision in 10 seconds
NewGLM 5.3 Prime vs GPT-5.6 Terra Pro
Pick GLM 5.3 Prime for lower cost; pick GPT-5.6 Terra Pro only if the larger context window matters more.
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Data confirmed:
Prices normalized to USD per 1M tokens
Sample workload: 1M input + 500K output
Budget verdict
Pick GLM 5.3 Prime for lower cost; pick GPT-5.6 Terra Pro only if the larger context window matters more.
On the standard 1M input plus 500K output workload, GLM 5.3 Prime is estimated at $7.2 vs $8 for GPT-5.6 Terra Pro, saving $0.8 (10% lower).
Cost-first pickGLM 5.3 Prime
Context-first pickGPT-5.6 Terra Pro
Sample savings$0.810%
10x traffic gap$8
GPT-5.6 Terra Pro has more context, but GLM 5.3 Prime saves $0.8 on the standard workload. At 10x that traffic, the same price gap is about $8. Use the calculator below to replace the sample workload with your own token volume.
Cost sensitivity
Workload Sensitivity
Cost winner changes by workload shape: input-heavy / RAG favors GPT-5.6 Terra Pro, balanced workload favors GLM 5.3 Prime, and output-heavy chatbot favors GLM 5.3 Prime.
| Workload shape | Token mix | Better pick | GLM 5.3 Prime | GPT-5.6 Terra Pro |
|---|---|---|---|---|
| Input-heavy / RAG | 5M input + 500K output | GPT-5.6 Terra Pro | $18.4 | $16 |
| Balanced workload | 1M input + 1M output | GLM 5.3 Prime | $11.6 | $14 |
| Output-heavy chatbot | 1M input + 5M output | GLM 5.3 Prime | $46.8 | $62 |
GLM 5.3 Prime is $3.2 cheaper per 1M output tokens (26.7% lower; 1.36x difference).
GPT-5.6 Terra Pro has 50K more context (1.05x larger).
GLM 5.3 Prime is $0.8 cheaper on the standard workload (10% lower).
Estimate your workload cost
Your Workload Cost
This estimate uses normalized public API pricing per 1M tokens. It is a planning aid, not a billing quote. Verify provider pricing, limits, and terms before production use.
Quick Decision
GPT-5.6 Terra Pro has the lower input price; GLM 5.3 Prime has the lower output price; GPT-5.6 Terra Pro offers the larger context window. For the 1M input plus 500K output sample, GLM 5.3 Prime is cheaper for the standard workload.
For a 1M input token plus 500K output token workload, the estimated API cost is $7.2 for GLM 5.3 Prime and $8 for GPT-5.6 Terra Pro.
Choose GLM 5.3 Prime when you care most about lower output-token price.
Choose GPT-5.6 Terra Pro when you care most about lower input-token price, and larger context window.
- On the standard 1M input plus 500K output workload, GLM 5.3 Prime is estimated at $7.2 vs $8 for GPT-5.6 Terra Pro, saving $0.8 (10% lower).
- GLM 5.3 Prime is $0.8 cheaper on the standard workload (10% lower).
- GPT-5.6 Terra Pro is $0.8 cheaper per 1M input tokens (28.6% lower; 1.4x difference).
- GLM 5.3 Prime is $3.2 cheaper per 1M output tokens (26.7% lower; 1.36x difference).
- GPT-5.6 Terra Pro has 50K more context (1.05x larger).
| Feature | NewGLM 5.3 Prime (Z.ai) | GPT-5.6 Terra Pro (OpenAI) |
|---|---|---|
| Input Price prompt tokens per 1M | $2.8 | $2 |
| Completion Price per 1M tokens | $8.8 | $12 |
| Sample Workload Cost 1M input + 500K output | $7.2 | $8 |
| Context Window | 1M | 1.05M |
| Release Date |
Use-Case Decision Matrix
| Use case | Better pick | Why |
|---|---|---|
| Budget-constrained production | GLM 5.3 Prime | On the standard 1M input plus 500K output workload, GLM 5.3 Prime is estimated at $7.2 vs $8 for GPT-5.6 Terra Pro, saving $0.8 (10% lower). |
| High-volume input processing | GPT-5.6 Terra Pro | Lower prompt-token price matters most when prompts, retrieved passages, or documents dominate the bill. |
| Long responses and chatbots | GLM 5.3 Prime | Lower output-token price matters most when assistants generate many completion tokens. |
| RAG or long-document work | GPT-5.6 Terra Pro | A larger context window leaves more room for retrieved passages, conversation history, or source files. |
Related Alternatives
- GLM 5.2 (free) can replace GLM 5.3 Prime when lower sample workload cost matters most: $0.
- GLM 4.5 Air (free) can replace GLM 5.3 Prime when lower sample workload cost matters most: $0.
- GLM 4 32B can replace GLM 5.3 Prime when lower sample workload cost matters most: $0.15.
- GLM 5.3 Flash (batch) can replace GLM 5.3 Prime when lower sample workload cost matters most: $0.16.
- Grok 4.20 Multi-Agent offers 2M context with $2.5 sample workload cost.
- Grok 4.20 offers 2M context with $2.5 sample workload cost.
- GLM 5.3 Flash offers 1.31M context with $0.4 sample workload cost.
- DeepSeek V4 Flash 0731 offers 1.31M context with $0.36 sample workload cost.
- MiMo-V2.6-Pro · Xiaomi · #1
- GLM 5.3 Flash · Z.ai · #2
- DeepSeek V4.1 Flash · DeepSeek · #3
- Hy4 preview · Tencent · #4
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Open OpenAI modelsGLM-5.3-Prime is the high-speed variant of Z.ai's GLM-5.3, inheriting its full capabilities while delivering 1.5–2× the output throughput through inference acceleration. It supports text input and output with a 1M-token...
GPT-5.6 Terra Pro is the same underlying model as [GPT-5.6 Terra](https://openrouter.ai/openai/gpt-5.6-terra), served with `reasoning.mode` set to `pro` for higher-quality responses on complex tasks. Learn more in OpenAI's docs: https://developers.openai.com/api/docs/guides/reasoning#reasoning-mode