Gemini 3.8 Flash vs GPT-6 Luna
Price, context window & benchmark comparison
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Verdict: GPT-6 Luna is 8.2× cheaper than Gemini 3.8 Flash on a typical 3:1 input/output mix. Gemini 3.8 Flash scores higher on the Artificial Analysis Intelligence Index (30.8 vs 27.9). GPT-6 Luna has the larger context window (1.1M vs 1M).
| Gemini 3.8 Flash | GPT-6 Luna | |
|---|---|---|
| Input price / 1M | $0.82 | $0.10 |
| Output price / 1M | $4.13 | $0.50 |
| Blended price (3:1) | $1.65 | $0.20 |
| Cached input / 1M | $0.0825 | $0.01 |
| Context window | 1M | 1.1M |
| Max output | 66K | 128K |
| Intelligence index | 30.8 | 27.9 |
| Coding index | 76.3 | — |
| Providers | 7 | 8 |
| Best provider uptime (30m) | 100.0% | 100.0% |
| Vision input | Yes | Yes |
| Reasoning | Yes | Yes |
| Tool calling | Yes | Yes |
| Released | 2026-09-02 | 2026-09-22 |
| Retirement | — | — |
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FAQ
Which is cheaper, Gemini 3.8 Flash or GPT-6 Luna?
GPT-6 Luna is 8.2× cheaper than Gemini 3.8 Flash on a typical 3:1 input/output mix.
Gemini 3.8 Flash vs GPT-6 Luna: which has a bigger context window?
Gemini 3.8 Flash: 1,048,576 tokens. GPT-6 Luna: 1,050,000 tokens.
How much would 1 million requests cost?
At 2,000 input + 500 output tokens per request: Gemini 3.8 Flash ≈ $3,713, GPT-6 Luna ≈ $450.00.
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