GPT-5.6 Luna is $0.2 cheaper per 1M input tokens (49.6% lower; 1.98x difference).
API cost decision in 10 seconds
🔥GPT-5.6 Luna vs 🔥DeepSeek V4 Pro 0423
Pick DeepSeek V4 Pro 0423 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 DeepSeek V4 Pro 0423 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, DeepSeek V4 Pro 0423 is estimated at $0.79 vs $0.8 for GPT-5.6 Luna, saving $0.0062 (0.8% lower).
Cost-first pickDeepSeek V4 Pro 0423
Context-first pickGPT-5.6 Luna
Sample savings$0.00620.8%
10x traffic gap$0.06
GPT-5.6 Luna has more context, but DeepSeek V4 Pro 0423 saves $0.0062 on the standard workload. At 10x that traffic, the same price gap is about $0.06. 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 Luna, balanced workload favors DeepSeek V4 Pro 0423, and output-heavy chatbot favors DeepSeek V4 Pro 0423.
| Workload shape | Token mix | Better pick | GPT-5.6 Luna | DeepSeek V4 Pro 0423 |
|---|---|---|---|---|
| Input-heavy / RAG | 5M input + 500K output | GPT-5.6 Luna | $1.6 | $2.38 |
| Balanced workload | 1M input + 1M output | DeepSeek V4 Pro 0423 | $1.4 | $1.19 |
| Output-heavy chatbot | 1M input + 5M output | DeepSeek V4 Pro 0423 | $6.2 | $4.37 |
DeepSeek V4 Pro 0423 is $0.41 cheaper per 1M output tokens (33.9% lower; 1.51x difference).
GPT-5.6 Luna has 1.42K more context (1x larger).
DeepSeek V4 Pro 0423 is $0.0062 cheaper on the standard workload (0.8% 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 Luna has the lower input price; DeepSeek V4 Pro 0423 has the lower output price; GPT-5.6 Luna offers the larger context window. For the 1M input plus 500K output sample, DeepSeek V4 Pro 0423 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 $0.79 for DeepSeek V4 Pro 0423.
Choose GPT-5.6 Luna when you care most about lower input-token price, and larger context window.
Choose DeepSeek V4 Pro 0423 when you care most about lower output-token price.
- On the standard 1M input plus 500K output workload, DeepSeek V4 Pro 0423 is estimated at $0.79 vs $0.8 for GPT-5.6 Luna, saving $0.0062 (0.8% lower).
- DeepSeek V4 Pro 0423 is $0.0062 cheaper on the standard workload (0.8% lower).
- GPT-5.6 Luna is $0.2 cheaper per 1M input tokens (49.6% lower; 1.98x difference).
- DeepSeek V4 Pro 0423 is $0.41 cheaper per 1M output tokens (33.9% lower; 1.51x difference).
- GPT-5.6 Luna has 1.42K more context (1x larger).
| Feature | 🔥GPT-5.6 Luna (OpenAI) | 🔥DeepSeek V4 Pro 0423 (DeepSeek) |
|---|---|---|
| Input Price prompt tokens per 1M | $0.2 | $0.3969 |
| Completion Price per 1M tokens | $1.2 | $0.7938 |
| Sample Workload Cost 1M input + 500K output | $0.8 | $0.79 |
| Context Window | 1.05M | 1.05M |
| Release Date | ||
| Popularity | #6 | #10 |
Use-Case Decision Matrix
| Use case | Better pick | Why |
|---|---|---|
| Budget-constrained production | DeepSeek V4 Pro 0423 | On the standard 1M input plus 500K output workload, DeepSeek V4 Pro 0423 is estimated at $0.79 vs $0.8 for GPT-5.6 Luna, saving $0.0062 (0.8% lower). |
| High-volume input processing | GPT-5.6 Luna | Lower prompt-token price matters most when prompts, retrieved passages, or documents dominate the bill. |
| Long responses and chatbots | DeepSeek V4 Pro 0423 | 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 $0.17 sample workload cost.
- DeepSeek V4 Flash Latest offers 1.31M context with $0.11 sample workload cost.
- Llama 4 Scout offers 1.31M context with $0.25 sample workload cost.
- DeepSeek V4 Flash 0731 · DeepSeek · #1
- MiMo-V2.5 · Xiaomi · #2
- Hy3 · Tencent · #3
- Ox Alpha · stealth · #4
Cheaper alternatives
Review low-cost models sorted by a standard 1M input plus 500K output workload.
Open cheapest modelsLarger context alternatives
Find models with larger context windows for RAG, long documents, and codebase review.
Open largest context modelsProvider catalogs
Compare models within provider hubs before choosing a final API vendor.
Open provider hubsOpenAI catalog
Review all tracked OpenAI models before deciding whether this matchup is the right shortlist.
Open OpenAI modelsDeepSeek catalog
Check other DeepSeek models with comparable pricing, context, or release timing.
Open DeepSeek modelsGPT-5.6 Luna is a fast, cost-efficient model in OpenAI's GPT-5.6 series. It is suited for high-volume, latency-sensitive tasks such as chat, classification, and lightweight agentic workflows, providing capable reasoning for...
DeepSeek V4 Pro is a large-scale Mixture-of-Experts model from DeepSeek with 1.6T total parameters and 49B activated parameters, supporting a 1M-token context window. It is designed for advanced reasoning, coding,...