Rate
Gemini 3.8 Flash vs GPT-5.6 Luna: price
GPT-5.6 Luna is 3.3× cheaper than Gemini 3.8 Flash for a typical chat workload (1,500 tokens in, 500 out).
| Item | Gemini 3.8 Flash | GPT-5.6 Luna |
|---|---|---|
| Input per 1M tokens | $0.75 | $0.20 |
| Output per 1M tokens | $3.75 | $1.20 |
| Cached input per 1M | $0.075 | $0.02 |
| 1,000 chat messages1,500 tokens in, 500 out each | $3.00 | $0.90 |
| Summarize a 50-page PDF30,000 tokens in, 1,000 out | $0.026 | $0.0072 |
| One coding-agent task60,000 tokens in, 4,000 out, no caching | $0.06 | $0.017 |
Gemini 3.8 Flash: Promo price through Dec 31, 2026; $1.50 in / $7.50 out from Jan 1, 2027.
List prices checked September 28, 2026. Price is half the story: see how people rate each one today.
Gemini 3.8 Flash vs GPT-5.6 Luna in numbers
Output, usually the bigger part of the bill, costs $3.75 on Gemini 3.8 Flash and $1.20 on GPT-5.6 Luna, so GPT-5.6 Luna is 3.1× cheaper there. Input costs $0.75 versus $0.20 per million tokens. For a coding-agent task (60,000 tokens in, 4,000 out) that is $0.06 on Gemini 3.8 Flash and $0.017 on GPT-5.6 Luna. Gemini 3.8 Flash accepts 1.05M tokens of context and GPT-5.6 Luna 1.05M tokens. Gemini 3.8 Flash came out on September 2, 2026 and GPT-5.6 Luna on July 9, 2026.
Gemini 3.8 Flash is made by Google; GPT-5.6 Luna by OpenAI. Estimate your own bill for both in the cost calculator.
Which one feels dumber today?
- Gemini 3.8 FlashGoogle
–no votes yet - GPT-5.6 LunaOpenAI–no votes yet
Frequently asked questions
Is Gemini 3.8 Flash or GPT-5.6 Luna cheaper?
GPT-5.6 Luna is 3.3× cheaper than Gemini 3.8 Flash for a typical chat workload (1,500 tokens in, 500 out). Output, usually the bigger part of the bill, costs $3.75 on Gemini 3.8 Flash and $1.20 on GPT-5.6 Luna, so GPT-5.6 Luna is 3.1× cheaper there.
Which is better, Gemini 3.8 Flash or GPT-5.6 Luna?
It depends on the task, and price is only part of it. Check how people rate each one today on the Gemini 3.8 Flash and GPT-5.6 Luna pages, and read what users report in Discussions.