Gemini 3.6 Flash vs GPT-5.6 Luna
Gemini 3.6 Flash was superseded by Gemini 3.8 Flash. GPT-5.6 Luna was superseded by GPT-6 Luna. The grades below are the last ones measured, so read them as history rather than as this week's board. See the current roster.
Gemini 3.6 Flash leads overall, C to D. GPT-5.6 Luna is the cheaper side per task (at most $0.012). By suite, Gemini 3.6 Flash takes real-world issues (C- to D) and vibe coding (C+ to F). Take GPT-5.6 Luna anyway when you want the side that is cheaper per task.Measured
Each agent graded on the same private suites, running headless through its own tools. Advantages are oriented so a win is a win, whichever way the metric runs.
Verdict: GPT-5.6 Luna vs Gemini 3.6 Flash
Gemini 3.6 Flash leads overall, C to D. By suite: Gemini 3.6 Flash takes real-world issues, C- to D (60% vs 45% capability); Gemini 3.6 Flash takes vibe coding, C+ to F (72% vs 25% capability). Only GPT-5.6 Luna has run spec planning. Gemini 3.6 Flash used 12.6% of Google AI Pro's weekly limit per pass, $0.039 per task at the listed price. GPT-5.6 Luna used <1% of ChatGPT Pro 5x's weekly limit per pass, at most $0.012 per task at the listed price. Per task, GPT-5.6 Luna costs at most $0.012 against Gemini 3.6 Flash's $0.039, so GPT-5.6 Luna is the cheaper side. Gemini 3.6 Flash is faster on real-world issues: a median task takes 2m 17s against 3m 7s. Both finished every task on it. Reasons to pick GPT-5.6 Luna anyway: it is cheaper per task (at most $0.012 vs $0.039).
Changed since the previous graded week: Gemini 3.6 Flash unchanged; GPT-5.6 Luna: spec planning D+ to C-, vibe coding C- to F.
| Dimension | Gemini 3.6 Flash | GPT-5.6 Luna | Advantage |
|---|---|---|---|
| Capability | 60% | 45% | +15% (Gemini 3.6 Flash leads) |
| Median task time | 2m 17s | 3m 7s | 50s faster (Gemini 3.6 Flash leads) |
| Approx. task cost | $0.039 / task | <$0.015 / task | $0.023 / task lower (GPT-5.6 Luna leads) |
Gemini 3.6 Flash: 12.6% of Google AI Pro (about 72.1% / 5h, 12.6% / 1w) per run. Its weekly limit holds 6 of the week's 33.6 5h windows. GPT-5.6 Luna: under 1% of ChatGPT Pro 5x per run. Each figure is a share of that agent's own plan, so there is no delta to draw.
Only GPT-5.6 Luna has run this suite, so there is no head-to-head yet.
| Dimension | Gemini 3.6 Flash | GPT-5.6 Luna | Advantage |
|---|---|---|---|
| Capability | 72% | 25% | +46% (Gemini 3.6 Flash leads) |
| Median task time | 1m 54s | 3m 40s | 1m 46s faster (Gemini 3.6 Flash leads) |
| Approx. task cost | $0.038 / task | <$0.230 / task | $0.192 / task lower (Gemini 3.6 Flash leads) |
Gemini 3.6 Flash: 0.8% of Google AI Pro (4.9% / 5h, 0.8% / 1w) per good solve. Its weekly limit holds 6 of the week's 33.6 5h windows. GPT-5.6 Luna: under 1% of ChatGPT Pro 5x per good solve. Each figure is a share of that agent's own plan, so there is no delta to draw.
Grades and deltas are comparable only within a suite version. See methodology.
Frequently asked questions
Which is better for coding, Gemini 3.6 Flash or GPT-5.6 Luna?
Gemini 3.6 Flash clears higher: tier 4 of 5 versus tier 1 for GPT-5.6 Luna on real-world@v3, our private suite of real-world coding problems. Latest measurement 2026-08-10.
Which is cheaper per task, Gemini 3.6 Flash or GPT-5.6 Luna?
Gemini 3.6 Flash used 12.6% of Google AI Pro's weekly limit per pass, $0.039 per task at the listed price. GPT-5.6 Luna used <1% of ChatGPT Pro 5x's weekly limit per pass, at most $0.012 per task at the listed price. Per task, GPT-5.6 Luna costs at most $0.012 against Gemini 3.6 Flash's $0.039, so GPT-5.6 Luna is the cheaper side.