Union Alpha is free for input tokens while GPT-5.6 Luna costs $0.2 per 1M tokens.
API cost decision in 10 seconds
🔥GPT-5.6 Luna vs NewUnion Alpha
Pick Union Alpha for lower cost; pick GPT-5.6 Luna only if the larger context window matters more.
Page updated:
Data confirmed:
Prices normalized to USD per 1M tokens
Sample workload: 1M input + 500K output
Budget verdict
Pick Union Alpha for lower cost; pick GPT-5.6 Luna only if the larger context window matters more.
On the standard 1M input plus 500K output workload, Union Alpha is estimated at $0 vs $0.8 for GPT-5.6 Luna, saving $0.8 (100% lower).
Cost-first pickUnion Alpha
Context-first pickGPT-5.6 Luna
Sample savings$0.8100%
10x traffic gap$8
GPT-5.6 Luna has more context, but Union Alpha 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
Union Alpha stays cheaper across input-heavy, balanced, and output-heavy sample workloads.
| Workload shape | Token mix | Better pick | GPT-5.6 Luna | Union Alpha |
|---|---|---|---|---|
| Input-heavy / RAG | 5M input + 500K output | Union Alpha | $1.6 | $0 |
| Balanced workload | 1M input + 1M output | Union Alpha | $1.4 | $0 |
| Output-heavy chatbot | 1M input + 5M output | Union Alpha | $6.2 | $0 |
Union Alpha is free for output tokens while GPT-5.6 Luna costs $1.2 per 1M tokens.
GPT-5.6 Luna has 787.86K more context (4.01x larger).
Union Alpha is free for the standard workload while the other model is estimated at $0.8.
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
Union Alpha has the lower input price; Union Alpha has the lower output price; GPT-5.6 Luna offers the larger context window. For the 1M input plus 500K output sample, Union Alpha is cheaper for the standard workload.
For a 1M input token plus 500K output token workload, the estimated API cost is $0.8 for GPT-5.6 Luna and $0 for Union Alpha.
Choose GPT-5.6 Luna when you care most about larger context window.
Choose Union Alpha when you care most about lower input-token price, and lower output-token price.
- On the standard 1M input plus 500K output workload, Union Alpha is estimated at $0 vs $0.8 for GPT-5.6 Luna, saving $0.8 (100% lower).
- Union Alpha is free for the standard workload while the other model is estimated at $0.8.
- Union Alpha is free for input tokens while GPT-5.6 Luna costs $0.2 per 1M tokens.
- Union Alpha is free for output tokens while GPT-5.6 Luna costs $1.2 per 1M tokens.
- GPT-5.6 Luna has 787.86K more context (4.01x larger).
| Feature | 🔥GPT-5.6 Luna (OpenAI) | NewUnion Alpha (stealth) |
|---|---|---|
| Input Price prompt tokens per 1M | $0.2 | $0 |
| Completion Price per 1M tokens | $1.2 | $0 |
| Sample Workload Cost 1M input + 500K output | $0.8 | $0 |
| Context Window | 1.05M | 262.14K |
| Release Date | ||
| Popularity | #2 |
Use-Case Decision Matrix
| Use case | Better pick | Why |
|---|---|---|
| Budget-constrained production | Union Alpha | On the standard 1M input plus 500K output workload, Union Alpha is estimated at $0 vs $0.8 for GPT-5.6 Luna, saving $0.8 (100% lower). |
| High-volume input processing | Union Alpha | Lower prompt-token price matters most when prompts, retrieved passages, or documents dominate the bill. |
| Long responses and chatbots | Union Alpha | Lower output-token price matters most when assistants generate many completion tokens. |
| RAG or long-document work | GPT-5.6 Luna | 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 Luna when lower sample workload cost matters most: $0.
- gpt-oss-20b (free) can replace GPT-5.6 Luna when lower sample workload cost matters most: $0.
- gpt-oss-20b can replace GPT-5.6 Luna when lower sample workload cost matters most: $0.1.
- gpt-oss-120b can replace GPT-5.6 Luna when lower sample workload cost matters most: $0.12.
- DeepSeek V4 Flash 0731 offers 1.31M context with $0.12 sample workload cost.
- GLM 5.3 Flash offers 1.31M context with $0.24 sample workload cost.
- GLM Flash Latest offers 1.31M context with $0.2 sample workload cost.
- DeepSeek V4 Flash Latest offers 1.31M context with $0.09 sample workload cost.
- Qwen3.8 Max (0902) · Qwen · #1
- Hy4 preview · Tencent · #3
- DeepSeek V4 Flash 0731 · DeepSeek · #4
- GLM 5.3 Flash · Z.ai · #5
Cheaper alternatives
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