Head to head
Gemini 3.6 Flash vs GPT-5.6 Luna
Which is better, Gemini 3.6 Flash or GPT-5.6 Luna?
Gemini 3.6 Flash finishes ahead of GPT-5.6 Luna on the index, 85.1 to 83.0. It is the stronger of the two on Craft, while GPT-5.6 Luna still leads on Value. Both are scored on the same rubric, in the same week, and neither placing is sponsored.
Updated
Gemini 3.6 Flash
19 of 73
85.1
Frontier answers at Flash speed, with a free tier you can actually build on.
GPT-5.6 Luna
30 of 73
83.0
Still cheap and still capable, but GPT-6 Luna costs half as much.
The four scores, side by side
| Score | Gemini 3.6 Flash | GPT-5.6 Luna | Difference |
|---|---|---|---|
| Craft | 85 | 80 | +5 |
| Speed | 90 | 92 | +2 |
| Control | 86 | 84 | +2 |
| Value | 82 | 86 | +4 |
| Index score | 85.1 | 83.0 | +2.1 |
Which to pick
Pick Gemini 3.6 Flash unless Value is what decides it for you, which is exactly where GPT-5.6 Luna is the better answer.
Gemini 3.6 Flash
Google stopped treating Flash as the budget option and it shows: 3.6 answers quickly, reads images and video natively, and holds its own against models that cost several times more per token. The free tier is generous enough to prototype a real product against, which no other frontier lab currently matches. Steering is the weak spot, with less control exposed than the competition offers.
Where it shines
- Genuinely fast for a model of this quality
- Native video and image understanding, not a bolted-on adapter
- Free tier is large enough to build a prototype against
GPT-5.6 Luna
Luna was the cheap end of the GPT-5.6 line, with a million-token window and the family's structured-output discipline at a fraction of its siblings' price. GPT-6 Luna now costs half as much again, and in October ChatGPT moved its free users to the newer model. The two score about the same, so the older one survives mainly where prompts were tuned against it.
Where it shines
- Million-token context at a low price
- Rated slightly higher than GPT-6 Luna by human voters
- Same tool-calling behaviour as its larger siblings