Gemini 3.1 Pro vs GPT-6 Astra
GPT-6 Astra leads overall, C to F. Gemini 3.1 Pro is about 1.4x cheaper per task. By suite, Gemini 3.1 Pro takes real-world issues (D+ to D) and GPT-6 Astra takes spec planning (C+ to F). Take Gemini 3.1 Pro anyway when you want the side that is cheaper per task and ahead on real-world issues.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-6 Astra vs Gemini 3.1 Pro
GPT-6 Astra leads overall, C to F. By suite: Gemini 3.1 Pro takes real-world issues, D+ to D (53% vs 43% capability); GPT-6 Astra takes spec planning, C+ to F (74% vs 21% capability); GPT-6 Astra takes vibe coding, C+ to F (74% vs 27% capability). Gemini 3.1 Pro used 15.9% of Google AI Pro's weekly limit per pass, $0.038 per task at the listed price. GPT-6 Astra used 22% of ChatGPT Plus's weekly limit per pass, $0.053 per task at the listed price; at the ~$100 tier the board defaults to that is an estimated ~4.4% of ChatGPT Pro 5x's weekly limit (est, about $0.053 per task). Per task, Gemini 3.1 Pro is about 1.4x cheaper ($0.038 vs $0.053). GPT-6 Astra is faster on real-world issues: a median task takes 2m 13s against 4m 53s. Both finished every task on it. Reasons to pick Gemini 3.1 Pro anyway: it is cheaper per task ($0.038 vs $0.053) and it leads on real-world issues (D+ to D).
Changed since W39: Gemini 3.1 Pro: real-world issues usage 9.8% to 14.8% of the weekly limit, spec planning usage 0.9% to 1.1% of the weekly limit, vibe coding usage 1.0% to 0.7% of the weekly limit; GPT-6 Astra has one graded week under this version (W40).
| Dimension | Gemini 3.1 Pro | GPT-6 Astra | Advantage |
|---|---|---|---|
| Capability | 53% | 43% | +10% (Gemini 3.1 Pro leads) |
| Median task time | 4m 53s | 2m 13s | 2m 40s faster (GPT-6 Astra leads) |
| Approx. task cost | $0.045 / task | $0.052 / task | $0.007 / task lower (Gemini 3.1 Pro leads) |
Gemini 3.1 Pro: 14.8% of Google AI Pro (88.9% / 5h, 14.8% / 1w) per run. Its weekly limit holds 6 of the week's 33.6 5h windows. GPT-6 Astra: 17.0% of ChatGPT Plus (112.0% / 5h, 17.0% / 1w) per run. Its weekly limit holds about 6 of the week's 33.6 5h windows. Each figure is a share of that agent's own plan, so there is no delta to draw.
| Dimension | Gemini 3.1 Pro | GPT-6 Astra | Advantage |
|---|---|---|---|
| Capability | 21% | 74% | +53% (GPT-6 Astra leads) |
| Median task time | 1m 46s | 3m 5s | 1m 20s faster (Gemini 3.1 Pro leads) |
| Approx. task cost | $0.013 / task | $0.057 / task | $0.045 / task lower (Gemini 3.1 Pro leads) |
Gemini 3.1 Pro: 1.1% of Google AI Pro (6.5% / 5h, 1.1% / 1w) per run. Its weekly limit holds 6 of the week's 33.6 5h windows. GPT-6 Astra: 5.0% of ChatGPT Plus (27.0% / 5h, 5.0% / 1w) per run. Its weekly limit holds about 6 of the week's 33.6 5h windows. Each figure is a share of that agent's own plan, so there is no delta to draw.
| Dimension | Gemini 3.1 Pro | GPT-6 Astra | Advantage |
|---|---|---|---|
| Capability | 27% | 74% | +47% (GPT-6 Astra leads) |
| Median task time | 4m 38s | 2m 40s | 1m 58s faster (GPT-6 Astra leads) |
| Approx. task cost | $0.034 / task | $0.046 / task | $0.012 / task lower (Gemini 3.1 Pro leads) |
Gemini 3.1 Pro: 0.7% of Google AI Pro (4.4% / 5h, 0.7% / 1w) per good solve. Its weekly limit holds 6 of the week's 33.6 5h windows. GPT-6 Astra: 1.0% of ChatGPT Plus (7.2% / 5h, 1.0% / 1w) per good solve. Its weekly limit holds about 6 of the week's 33.6 5h windows. 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 3.1 Pro or GPT-6 Astra?
Gemini 3.1 Pro clears higher: tier 3 of 5 versus tier 2 for GPT-6 Astra on real-world@v3, our private suite of real-world coding problems. Latest measurement 2026-09-28.
Which is cheaper per task, Gemini 3.1 Pro or GPT-6 Astra?
Gemini 3.1 Pro used 15.9% of Google AI Pro's weekly limit per pass, $0.038 per task at the listed price. GPT-6 Astra used 22% of ChatGPT Plus's weekly limit per pass, $0.053 per task at the listed price; at the ~$100 tier the board defaults to that is an estimated ~4.4% of ChatGPT Pro 5x's weekly limit (est, about $0.053 per task). Per task, Gemini 3.1 Pro is about 1.4x cheaper ($0.038 vs $0.053).