High-volume, cost-sensitive work
Choose GPT-5.6 Luna
GPT-5.6 Luna costs 14% less on a typical mix of three input tokens for every output token ($0.45 against $0.53 per million tokens).
DeepSeek V4.1 Flash vs GPT-5.6 Luna: price, context and capabilities
Choose DeepSeek V4.1 Flash for reused prompts and documents (RAG, agents), the hardest reasoning tasks and the latest release. Choose GPT-5.6 Luna for high-volume, cost-sensitive work.
In short
- GPT-5.6 Luna is 14% cheaper than DeepSeek V4.1 Flash at the headline price ($0.45 / 1M tokens vs $0.525 / 1M tokens).
- GPT-5.6 Luna reads more per request: 1.05M tokens against 1M.
- DeepSeek V4.1 Flash is the newer model (October 2026, against Jul 9, 2026).
- Only GPT-5.6 Luna offers batch api.
Which should you choose?
Each answer below comes straight from the published prices, specifications and independent benchmark results.
Reused prompts and documents (RAG, agents)
Choose DeepSeek V4.1 Flash
DeepSeek V4.1 Flash charges <$0.01 per million cached input tokens, against $0.02 for GPT-5.6 Luna.
Hardest reasoning tasks
Choose DeepSeek V4.1 Flash
DeepSeek V4.1 Flash scores 45.1 on the Artificial Analysis Intelligence Index, against 37.3 for GPT-5.6 Luna.
Reasoning over long documents
Either one
They are practically level on Long-context reasoning (AA-LCR) (82.7% and 83.7%).
Latest release
Choose DeepSeek V4.1 Flash
DeepSeek V4.1 Flash is the newer release (October 2026, against Jul 9, 2026 for GPT-5.6 Luna).
Monthly cost at three volumes
| Volume | DeepSeek V4.1 Flash | GPT-5.6 Luna | Difference |
|---|---|---|---|
| Prototype: 1M input, 250K output tokens | $0.60 | $0.50 | GPT-5.6 Luna, $0.10 less |
| Production: 20M input, 5M output tokens | $12.00 | $10.00 | GPT-5.6 Luna, $2.00 less |
| Scale: 500M input, 100M output tokens | $270.00 | $220.00 | GPT-5.6 Luna, $50.00 less |
Standard rates, without caching or batch discounts. Volumes are per month.
Specifications side by side
| DeepSeek V4.1 Flash | GPT-5.6 Luna | |
|---|---|---|
| Provider | DeepSeek | OpenAI |
| Category | Language models | Language models |
| Status | Generally available | Generally available |
| Headline price | $0.525 / 1M tokens | $0.45 / 1M tokens |
| Input | $0.30 / 1M tokens | $0.20 / 1M tokens |
| Output | $1.20 / 1M tokens | $1.20 / 1M tokens |
| Cached input | $0.006 / 1M tokens | $0.02 / 1M tokens |
| Context window | 1M | 1.05M |
| Max output | 384k | 128k |
| Released | October 2026 | Jul 9, 2026 |
| Knowledge cutoff | No data | February 2026 |
| Licence | Proprietary | Proprietary |
| Capabilities | Vision, Reasoning, Tool calling, Structured output, Prompt caching | Vision, Reasoning, Tool calling, Structured output, Prompt caching, Batch API |
| API model id | deepseek-flash | gpt-5.6-luna |
Benchmarks side by side
Leader in bold.
| Benchmark | DeepSeek V4.1 Flash | GPT-5.6 Luna |
|---|---|---|
| Intelligence Index | 45.1 | 37.3 |
| SciCode | 55.9% | 53.6% |
| Humanity's Last Exam | 43.3% | 39.5% |
| MMMU-Pro (visual reasoning) | 80.6% | 78.6% |
| Long-context reasoning (AA-LCR) | 82.7% | 83.7% |
| GPQA Diamond | No data | 91.1% |
Independent evaluations by Artificial Analysis, run the same way for every model, at the reasoning setting shown. Percentages unless marked as an index.
Frequently asked questions
Should I choose DeepSeek V4.1 Flash or GPT-5.6 Luna?
Choose DeepSeek V4.1 Flash for reused prompts and documents (RAG, agents), the hardest reasoning tasks and the latest release. Choose GPT-5.6 Luna for high-volume, cost-sensitive work.
Which is cheaper, DeepSeek V4.1 Flash or GPT-5.6 Luna?
GPT-5.6 Luna is 14% cheaper than DeepSeek V4.1 Flash at the headline price ($0.45 / 1M tokens vs $0.525 / 1M tokens).
Which has the larger context window, DeepSeek V4.1 Flash or GPT-5.6 Luna?
GPT-5.6 Luna reads more per request: 1.05M tokens against 1M.
What is the difference between DeepSeek V4.1 Flash and GPT-5.6 Luna?
DeepSeek V4.1 Flash is made by DeepSeek and GPT-5.6 Luna by OpenAI. GPT-5.6 Luna is 14% cheaper than DeepSeek V4.1 Flash at the headline price ($0.45 / 1M tokens vs $0.525 / 1M tokens). GPT-5.6 Luna reads more per request: 1.05M tokens against 1M. DeepSeek V4.1 Flash is the newer model (October 2026, against Jul 9, 2026). Only GPT-5.6 Luna offers batch api.
How much do DeepSeek V4.1 Flash and GPT-5.6 Luna cost per month?
At 20 million input and 5 million output tokens a month, DeepSeek V4.1 Flash costs $12.00 and GPT-5.6 Luna costs $10.00, at standard rates.
Which is newer, DeepSeek V4.1 Flash or GPT-5.6 Luna?
DeepSeek V4.1 Flash was released on October 2026 and GPT-5.6 Luna on Jul 9, 2026.