GPT-6 Luna vs Gemini 3.5 Flash-Lite
There is no quality verdict yet: the AIGROW small-business benchmark has not run GPT-6 Luna. On price, GPT-6 Luna costs less: $0.10 in and $0.50 out per million tokens, against $0.30 in and $2.50 out for Gemini 3.5 Flash-Lite.
US dollars, standard rate, shortest context band. Price only: the benchmark has not run both.
- GPT-6 Luna
- $0.50
- Gemini 3.5 Flash-Lite
- $1.90
- GPT-6 Luna, per M tokens
- $0.10 / $0.50
- Gemini 3.5 Flash-Lite, per M tokens
- $0.30 / $2.50
3,000 tokens in and 400 out each, at list price.
OpenAI's and Google's newest budget models for high-volume tasks, with Luna cheaper on input and output. 1,000 support replies cost $1.90 on Gemini 3.5 Flash-Lite and $0.50 on GPT-6 Luna, so Gemini 3.5 Flash-Lite costs 3.8 times as much. GPT-6 Luna was released on 22 Sep 2026, Gemini 3.5 Flash-Lite was released on 21 Jul 2026.
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.
- GPT-6 Luna
- On the OpenAI API, GPT-6 Luna costs $0.10 per million input tokens and $0.50 per million output tokens. In ChatGPT, it comes with the free plan, and the cheapest paid plan with it is Go at $8/mo. Plan prices read 14 October 2026.
- Gemini 3.5 Flash-Lite
- On the Google API, Gemini 3.5 Flash-Lite costs $0.30 per million input tokens and $2.50 per million output tokens.
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 | GPT-6 Luna | Gemini 3.5 Flash-Lite |
|---|---|---|
| Maker | OpenAI | |
| Tier | Small and fast | Small and fast |
| Input, per M tokens | $0.10 | $0.30 |
| Output, per M tokens | $0.50 | $2.50 |
| Cached input | $0.01 | $0.03 |
| Context window | 1.05M | 1.05M |
| Released | 22 Sep 2026 | 21 Jul 2026 |
| Weights | Closed 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 | GPT-6 Luna | Gemini 3.5 Flash-Lite | Cheaper |
|---|---|---|---|
| Support reply3,000 in, 400 out. | $0.50 | $1.90 | GPT-6 Luna, 74% less |
| Document summary25,000 in, 1,000 out. | $3.00 | $10.00 | GPT-6 Luna, 70% less |
| Agent task80,000 in (70,000 cached), 3,000 out. | $3.20 | $12.60 | GPT-6 Luna, 75% less |
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.
- GPT-6 Luna
- Requests above 272K input tokens bill 2x input and 1.5x output ($0.20 / $0.75, cached $0.02). Cache write $0.125. Batch and Flex 50% off, Fast mode 2x. Data residency adds 10%. OpenAI’s pricing page
- Gemini 3.5 Flash-Lite
- Same price for text, image, video and audio input. Batch 50% off. Cache storage $1.00 per MTok per hour. Google’s pricing page
Other comparisons
Every head to head on the list that involves GPT-6 Luna or Gemini 3.5 Flash-Lite.
Compare GPT-6 Luna and Gemini 3.5 Flash-Lite with 44 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 15 October 2026