Budget Showdown
GPT-5.6 Luna vs DeepSeek V4 Flash
Two budget models, vastly different prices. Is OpenAI's budget tier worth 7x more than DeepSeek?
Last verified: Jul 13, 2026 · See all 67 models ranked →
| Feature | GPT-5.6 Luna | DeepSeek V4 Flash |
|---|---|---|
| Input price (per 1M tokens) | $1.00 | $0.14 |
| Output price (per 1M tokens) | $6.00 | $0.28 |
| Context window | 1.05M tokens | 1M tokens |
| Standard request cost | $0.0039 | $0.000324 |
| Cost ratio | 7x input, 21x output | Baseline |
| Provider | OpenAI | DeepSeek |
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OpenAI
GPT-5.6 Luna
$0
estimated monthly cost
Input cost$0
Output cost$0
Per request$0
DeepSeek
DeepSeek V4 Flash
$0
estimated monthly cost
Input cost$0
Output cost$0
Per request$0
The Verdict
DeepSeek V4 Flash wins on price. GPT-5.6 Luna wins on context and ecosystem.
DeepSeek V4 Flash ($0.14/$0.28) is 86% cheaper on input and 95% cheaper on output than GPT-5.6 Luna ($1/$6). For pure cost efficiency, DeepSeek is unbeatable. But GPT-5.6 Luna has a 5% larger context window (1.05M vs 1M) and comes with OpenAI's ecosystem, tooling, and reliability SLAs.
When to Choose DeepSeek V4 Flash
- Cost is king: At $0.14/$0.28, DeepSeek is the cheapest option with a 1M context window. For high-volume, cost-sensitive workloads, nothing beats it.
- Simple tasks: Classification, extraction, summarization, data labeling — DeepSeek handles these at 95% less cost than GPT-5.6 Luna.
- Batch processing: Non-real-time workloads where latency doesn't matter. DeepSeek's pricing makes it ideal for batch jobs.
- Prototyping: Build and test your AI features at minimal cost, then decide if you need to upgrade to OpenAI.
When to Choose GPT-5.6 Luna
- OpenAI ecosystem: If you're already using OpenAI's API and want to stay in their ecosystem with consistent tooling.
- Larger context: The 1.05M context window is 5% larger than DeepSeek's 1M. For processing very large documents, this matters.
- Reliability SLAs: OpenAI offers enterprise SLAs that DeepSeek doesn't match. For production systems with uptime requirements, this matters.
- Reasoning quality: GPT-5.6 Luna may offer better reasoning quality for complex tasks — test both for your specific use case.
Cost Comparison: Real-World Scenarios
High-Volume Chatbot (5,000 requests/day, 1,000 input, 200 output)
GPT-5.6 Luna$510.00/mo
DeepSeek V4 Flash$36.40/mo
Monthly savings$473.60/mo (93%)
Code Generation (200 requests/day, 3,000 input, 1,200 output)
GPT-5.6 Luna$594.00/mo
DeepSeek V4 Flash$28.56/mo
Monthly savings$565.44/mo (95%)
Data Extraction (1,000 requests/day, 500 input, 300 output)
GPT-5.6 Luna$240.00/mo
DeepSeek V4 Flash$7.02/mo
Monthly savings$232.98/mo (97%)
Full Comparison Table
| Model | Input/1M | Output/1M | vs GPT-5.6 Luna | Context |
|---|---|---|---|---|
| GPT-5.6 Luna | $1.00 | $6.00 | — | 1.05M |
| DeepSeek V4 Flash | $0.14 | $0.28 | 86% cheaper input, 95% cheaper output | 1M |
| DeepSeek V4 Pro | $0.44 | $0.87 | 56% cheaper input, 85% cheaper output | 1M |
| Gemini 2.5 Flash-Lite | $0.10 | $0.40 | 90% cheaper input, 93% cheaper output | 1M |
| GPT-4o mini | $0.15 | $0.60 | 85% cheaper input, 90% cheaper output | 128K |
| Mistral Small 4 | $0.15 | $0.60 | 85% cheaper input, 90% cheaper output | 128K |
| GPT-5.6 Terra | $2.50 | $15.00 | 150% more expensive input, 150% more output | 1.05M |
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