DeepSeek V4.1 Flash vs GPT-5.6 Luna
GPT-5.6 Luna is the better buy: the AIGROW small-business benchmark cannot tell the two apart, and GPT-5.6 Luna has the lower list price. DeepSeek V4.1 Flash passed 18 of 20 tasks and costs $0.30 in and $1.20 out per million tokens; GPT-5.6 Luna passed 16 and costs $0.20 in and $1.20 out.
AIGROW credit covers Claude Opus 5.5, Claude Fable 5.2, Claude Fable 5.1, GPT-6 Astra, Claude Sonnet 5.5, GPT-6.1 Sol, GPT-6.1 Terra, Grok 4.7 and Gemini 4 Argon. GPT-6.1 Sol below list price
$25 a month brings $110 of API credit and cancels any time; $25 once buys $100. US dollars, standard rate, shortest context band. Cost per pass from the AIGROW small-business benchmark. Newer model: GPT-6 Luna
- DeepSeek V4.1 Flash
- $1.05
- Tasks passed
- 18 of 20
- GPT-5.6 Luna
- $0.677
- Tasks passed
- 16 of 20
AIGROW small-business benchmark, failed runs included.
Two low-cost APIs for bulk work, with DeepSeek cheaper again off-peak. GPT-5.6 Luna costs $0.677 per 1,000 passing answers on the AIGROW small-business benchmark, DeepSeek V4.1 Flash $1.05. 1,000 support replies cost $1.38 on DeepSeek V4.1 Flash and $1.08 on GPT-5.6 Luna, so DeepSeek V4.1 Flash costs 28% more.
What each one costs
The API price per million tokens and the cheapest app plan with each model, from the makers’ own pages. Each name opens that model’s full price page.
- DeepSeek V4.1 Flash
- On the DeepSeek API, DeepSeek V4.1 Flash costs $0.30 per million input tokens and $1.20 per million output tokens.
- GPT-5.6 Luna
- On the OpenAI API, GPT-5.6 Luna costs $0.20 per million input tokens and $1.20 per million output tokens. In ChatGPT, the cheapest plan with it is Plus at $20/mo. Plan prices read 22 October 2026.
Side by side
Each maker’s published rate for its standard tier. Cached input is what a repeated prompt prefix costs once the provider has stored it.
| Fact | DeepSeek V4.1 Flash | GPT-5.6 Luna |
|---|---|---|
| Maker | DeepSeek | OpenAI |
| Tier | Small and fast | Small and fast |
| Input, per M tokens | $0.30 | $0.20 |
| Output, per M tokens | $1.20 | $1.20 |
| Cached input | $0.006 | $0.02 |
| Context window | 1M | 1.05M |
| Released | 10 Sep 2026 | 9 Jul 2026 |
| Weights | Open weights | Closed weights |
What a job costs on each
1,000 runs of each job at the two list prices. The gap moves from job to job because the models price input, output and cached context differently.
| Job | DeepSeek V4.1 Flash | GPT-5.6 Luna | Cheaper |
|---|---|---|---|
| Support reply3,000 in, 400 out. | $1.38 | $1.08 | GPT-5.6 Luna, 22% less |
| Document summary25,000 in, 1,000 out. | $8.70 | $6.20 | GPT-5.6 Luna, 29% less |
| Agent task80,000 in (70,000 cached), 3,000 out. | $7.02 | $7.00 | Even |
The token counts are ours, chosen to look like real work; the prices are the makers’. A model with no published cache price bills the agent task’s repeated context at its full input rate.
The small print
What each base rate leaves out, from the makers’ own pages: surcharges, discounts, promotions and cache pricing.
- DeepSeek V4.1 Flash
- Peak-hour rate, recorded as the list price. Off-peak is half: $0.15 / $0.60, cache hit $0.003. API name deepseek-flash, which serves DeepSeek-V4.1-Flash-1017 since 2026-10-17 at unchanged prices. Max output 384K. DeepSeek’s pricing page
- GPT-5.6 Luna
- Nano tier of the 5.6 family. Price cut 80% on 2026-07-30. Requests above 272K input tokens bill 2x input and 1.5x output ($0.40 / $1.80). Cache write $0.25. Batch and Flex 50% off. Data residency adds 10%. OpenAI’s pricing page
Other comparisons
Every head to head on the list that involves DeepSeek V4.1 Flash or GPT-5.6 Luna.
Compare DeepSeek V4.1 Flash and GPT-5.6 Luna with 52 other models
The price list sets every model’s input and output price side by side, with what a support reply, a document summary and an agent task cost on each.
Prices checked 12 November 2026