DeepSeek V4.1 Flash vs GPT-6 Luna
DeepSeek V4.1 Flash costs $0.30 / $1.20 and GPT-6 Luna costs $0.10 / $0.50 per million input / output tokens. At a typical 3:1 mix, GPT-6 Luna is 2.6× cheaper than DeepSeek V4.1 Flash.
DeepSeek V4.1 Flash
DeepSeek
Input
$0.30
per 1M
Output
$1.20
per 1M
Cached
$0.006
1M context
Input
$0.10
per 1M
Output
$0.50
per 1M
Cached
$0.010
1.05M context
Side by side
Green marks the cheaper price, larger context window, bigger discount or higher score.
| Detail | DeepSeek V4.1 Flash | GPT-6 Luna |
|---|---|---|
| Input per 1M | $0.30 | $0.10 |
| Output per 1M | $1.20 | $0.50 |
| Blended per 1M (3:1) | $0.52 | $0.20 |
| Cached input per 1M | $0.006 | $0.010 |
| Batch or off-peak discount | 50% (off-peak) | 50% (batch) |
| Long prompts | Same rate at any length | Over 272K: 2× in, 1.5× out |
| Context window | 1M | 1.05M |
| Released | 10 Sep 2026 | 22 Sep 2026 |
| Open weights | No | No |
| Verified | 27 Sep 2026 | 27 Sep 2026 |
Sources: DeepSeek pricing and OpenAI pricing.
Monthly cost on three workloads
List prices, no batch discount. The cached share applies where a model has a cache rate.
| Workload | DeepSeek V4.1 Flash | GPT-6 Luna | Difference |
|---|---|---|---|
| Customer chat assistant50,000 conversations a month, about 2,000 tokens in and 400 out each; 50% cached | $39.30 | $15.50 | $23.80 |
| Document Q&A (RAG)20,000 questions a month over retrieved documents, 12,000 in and 600 out; 30% cached | $65.23 | $23.52 | $41.71 |
| Coding agent400 tasks a month, 40 steps each with a growing context; 85% cached | $47.18 | $21.63 | $25.55 |
How they differ
- GPT-6 Luna is cheaper on input ($0.10 vs $0.30).
- GPT-6 Luna is cheaper on output ($0.50 vs $1.20), which matters most for long answers and reasoning models.
- GPT-6 Luna accepts longer prompts (1.05M vs 1M tokens).
- Cached input is cheaper on DeepSeek V4.1 Flash ($0.006 vs $0.01), which favours agents and chat apps that resend the same context.
- Only GPT-6 Luna offers a batch discount for jobs that can wait.
Recent changes
All changes- OpenAI launched GPT-6 Sol at $2 / $10 and GPT-6 Luna at $0.10 / $0.50.
- DeepSeek V4.1 Flash replaced V4 Flash at $0.30 / $1.20 peak ($0.15 / $0.60 off-peak).
- OpenAI launched GPT-6 Astra at $10 / $50, its most expensive standard model.
- DeepSeek V4 Pro moved to peak and off-peak pricing: $1.32 / $3.96 at peak, down from $1.74 on input and up from $3.48 on output.
- DeepSeek discontinued the deepseek-chat (V3.2) and deepseek-reasoner (R1) endpoints.
