GPT-5.6 Terra Pro is $1 cheaper per 1M input tokens (33.3% lower; 1.5x difference).
API cost decision in 10 seconds
GPT-5.6 Terra Pro vs Aion-3.0
Pick Aion-3.0 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 Aion-3.0 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, Aion-3.0 is estimated at $6 vs $8 for GPT-5.6 Terra Pro, saving $2 (25% lower).
Cost-first pickAion-3.0
Context-first pickGPT-5.6 Terra Pro
Sample savings$225%
10x traffic gap$20
GPT-5.6 Terra Pro has more context, but Aion-3.0 saves $2 on the standard workload. At 10x that traffic, the same price gap is about $20. 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 Aion-3.0, and output-heavy chatbot favors Aion-3.0.
| Workload shape | Token mix | Better pick | GPT-5.6 Terra Pro | Aion-3.0 |
|---|---|---|---|---|
| Input-heavy / RAG | 5M input + 500K output | GPT-5.6 Terra Pro | $16 | $18 |
| Balanced workload | 1M input + 1M output | Aion-3.0 | $14 | $9 |
| Output-heavy chatbot | 1M input + 5M output | Aion-3.0 | $62 | $33 |
Aion-3.0 is $6 cheaper per 1M output tokens (50% lower; 2x difference).
GPT-5.6 Terra Pro has 918.93K more context (8.01x larger).
Aion-3.0 is $2 cheaper on the standard workload (25% 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; Aion-3.0 has the lower output price; GPT-5.6 Terra Pro offers the larger context window. For the 1M input plus 500K output sample, Aion-3.0 is cheaper for the standard workload.
For a 1M input token plus 500K output token workload, the estimated API cost is $8 for GPT-5.6 Terra Pro and $6 for Aion-3.0.
Choose GPT-5.6 Terra Pro when you care most about lower input-token price, and larger context window.
Choose Aion-3.0 when you care most about lower output-token price.
- On the standard 1M input plus 500K output workload, Aion-3.0 is estimated at $6 vs $8 for GPT-5.6 Terra Pro, saving $2 (25% lower).
- Aion-3.0 is $2 cheaper on the standard workload (25% lower).
- GPT-5.6 Terra Pro is $1 cheaper per 1M input tokens (33.3% lower; 1.5x difference).
- Aion-3.0 is $6 cheaper per 1M output tokens (50% lower; 2x difference).
- GPT-5.6 Terra Pro has 918.93K more context (8.01x larger).
| Feature | GPT-5.6 Terra Pro (OpenAI) | Aion-3.0 (AionLabs) |
|---|---|---|
| Input Price prompt tokens per 1M | $2 | $3 |
| Completion Price per 1M tokens | $12 | $6 |
| Sample Workload Cost 1M input + 500K output | $8 | $6 |
| Context Window | 1.05M | 131.07K |
| Release Date |
Use-Case Decision Matrix
| Use case | Better pick | Why |
|---|---|---|
| Budget-constrained production | Aion-3.0 | On the standard 1M input plus 500K output workload, Aion-3.0 is estimated at $6 vs $8 for GPT-5.6 Terra Pro, saving $2 (25% 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 | Aion-3.0 | 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
- gpt-oss-120b (free) can replace GPT-5.6 Terra Pro when lower sample workload cost matters most: $0.
- gpt-oss-20b (free) can replace GPT-5.6 Terra Pro when lower sample workload cost matters most: $0.
- gpt-oss-20b can replace GPT-5.6 Terra Pro when lower sample workload cost matters most: $0.1.
- gpt-oss-120b can replace GPT-5.6 Terra Pro when lower sample workload cost matters most: $0.12.
- 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.
- DeepSeek V4 Flash 0731 offers 1.31M context with $0.17 sample workload cost.
- DeepSeek V4 Flash Latest offers 1.31M context with $0.11 sample workload cost.
- DeepSeek V4 Flash 0731 · DeepSeek · #1
- MiMo-V2.5 · Xiaomi · #2
- Hy3 · Tencent · #3
- Ox Alpha · stealth · #4
Cheaper alternatives
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Open AionLabs modelsGPT-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
Aion-3.0 is a multi-model roleplaying and storytelling system from AionLabs, built on the GLM family of models. It uses a collaborative generation process in which multiple specialized models each contribute...