Gemini 3.1 Pro vs GPT-5.6 Terra
GPT-5.6 Terra leads overall, D to F. GPT-5.6 Terra is about 2.0x cheaper per task. By suite, real-world issues is even at D+ and GPT-5.6 Terra takes spec planning (D+ to F). The data gives no reason to pick Gemini 3.1 Pro over GPT-5.6 Terra this week.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 Terra vs Gemini 3.1 Pro
GPT-5.6 Terra leads overall, D to F. By suite: real-world issues is even at D+ (53% vs 50% capability); GPT-5.6 Terra takes spec planning, D+ to F (53% vs 21% capability); vibe coding is even at F (27% vs 34% 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-5.6 Terra used 8% of ChatGPT Plus's weekly limit per pass, $0.019 per task at the listed price; at the ~$100 tier the board defaults to that is an estimated ~1.6% of ChatGPT Pro 5x's weekly limit (est, about $0.019 per task). Per task, GPT-5.6 Terra is about 2.0x cheaper ($0.019 vs $0.038). GPT-5.6 Terra is faster on real-world issues: a median task takes 2m 18s against 4m 53s. Both finished every task on it. The data gives no reason to pick Gemini 3.1 Pro over GPT-5.6 Terra this week.
Changed since the previous graded week: 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-5.6 Terra: real-world issues D to D+, real-world issues usage 9.2% to 7% of the weekly limit, spec planning C- to D+, spec planning usage 2.0% to 1% of the weekly limit, vibe coding F to D, vibe coding usage 0.5% to 0.6% of the weekly limit.
| Dimension | Gemini 3.1 Pro | GPT-5.6 Terra | Advantage |
|---|---|---|---|
| Capability | 53% | 50% | +3% (Gemini 3.1 Pro leads) |
| Median task time | 4m 53s | 2m 18s | 2m 35s faster (GPT-5.6 Terra leads) |
| Approx. task cost | $0.045 / task | $0.021 / task | $0.024 / task lower (GPT-5.6 Terra 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-5.6 Terra: 7.0% of ChatGPT Plus (46.0% / 5h, 7.0% / 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-5.6 Terra | Advantage |
|---|---|---|---|
| Capability | 21% | 53% | +32% (GPT-5.6 Terra leads) |
| Median task time | 1m 46s | 2m 37s | 52s faster (Gemini 3.1 Pro leads) |
| Approx. task cost | $0.013 / task | $0.011 / task | $0.001 / task lower (GPT-5.6 Terra 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-5.6 Terra: 1.0% of ChatGPT Plus (10.0% / 5h, 1.0% / 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-5.6 Terra | Advantage |
|---|---|---|---|
| Capability | 27% | 34% | +7% (GPT-5.6 Terra leads) |
| Median task time | 4m 38s | 2m 47s | 1m 50s faster (GPT-5.6 Terra leads) |
| Approx. task cost | $0.034 / task | $0.028 / task | $0.007 / task lower (GPT-5.6 Terra 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-5.6 Terra: 0.6% of ChatGPT Plus (3.0% / 5h, 0.6% / 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-5.6 Terra?
Gemini 3.1 Pro clears higher: tier 3 of 5 versus tier 2 for GPT-5.6 Terra 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-5.6 Terra?
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-5.6 Terra used 8% of ChatGPT Plus's weekly limit per pass, $0.019 per task at the listed price; at the ~$100 tier the board defaults to that is an estimated ~1.6% of ChatGPT Pro 5x's weekly limit (est, about $0.019 per task). Per task, GPT-5.6 Terra is about 2.0x cheaper ($0.019 vs $0.038).