GPT-6 Luna vs Gemini 3.5 Flash-Lite
GPT-6 Luna costs $0.10 / $0.50 and Gemini 3.5 Flash-Lite costs $0.30 / $2.50 per million input / output tokens. At a typical 3:1 mix, GPT-6 Luna is 4.3× cheaper than Gemini 3.5 Flash-Lite.
Input
$0.10
per 1M
Output
$0.50
per 1M
Cached
$0.010
1.05M context
Gemini 3.5 Flash-Lite
Google
Input
$0.30
per 1M
Output
$2.50
per 1M
Cached
$0.030
1M context
Side by side
Green marks the cheaper price, larger context window, bigger discount or higher score.
| Detail | GPT-6 Luna | Gemini 3.5 Flash-Lite |
|---|---|---|
| Input per 1M | $0.10 | $0.30 |
| Output per 1M | $0.50 | $2.50 |
| Blended per 1M (3:1) | $0.20 | $0.85 |
| Cached input per 1M | $0.010 | $0.030 |
| Batch or off-peak discount | 50% (batch) | 50% (batch) |
| Long prompts | Over 272K: 2× in, 1.5× out | Same rate at any length |
| Context window | 1.05M | 1M |
| Released | 22 Sep 2026 | 21 Jul 2026 |
| Open weights | No | No |
| Verified | 27 Sep 2026 | 27 Sep 2026 |
Sources: OpenAI pricing and Gemini API pricing.
Monthly cost on three workloads
List prices, no batch discount. The cached share applies where a model has a cache rate.
| Workload | GPT-6 Luna | Gemini 3.5 Flash-Lite | Difference |
|---|---|---|---|
| Customer chat assistant50,000 conversations a month, about 2,000 tokens in and 400 out each; 50% cached | $15.50 | $66.50 | $51.00 |
| Document Q&A (RAG)20,000 questions a month over retrieved documents, 12,000 in and 600 out; 30% cached | $23.52 | $82.56 | $59.04 |
| Coding agent400 tasks a month, 40 steps each with a growing context; 85% cached | $21.63 | $72.88 | $51.25 |
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 $2.50), 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 GPT-6 Luna ($0.01 vs $0.03), which favours agents and chat apps that resend the same context.
Recent changes
All changes- OpenAI launched GPT-6 Sol at $2 / $10 and GPT-6 Luna at $0.10 / $0.50.
- OpenAI launched GPT-6 Astra at $10 / $50, its most expensive standard model.
- ▼ 50%Google launched Gemini 3.6 Flash at $0.75 / $3.75, half the price of 3.5 Flash, and Gemini 3.5 Flash-Lite at $0.30 / $2.50.
