Gemini 3.1 Pro vs Kimi K3 256K
Kimi K3 256K leads overall, D+ to F. Gemini 3.1 Pro is about 3.8x cheaper per task. By suite, Kimi K3 256K takes real-world issues (C- to D+) and spec planning (C- to F). Take Gemini 3.1 Pro 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: Kimi K3 256K vs Gemini 3.1 Pro
Kimi K3 256K leads overall, D+ to F. By suite: Kimi K3 256K takes real-world issues, C- to D+ (60% vs 53% capability); Kimi K3 256K takes spec planning, C- to F (56% 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. Kimi K3 256K used 31% of Kimi Allegretto's weekly limit per pass, $0.146 per task at the listed price. Per task, Gemini 3.1 Pro is about 3.8x cheaper ($0.038 vs $0.146). Kimi K3 256K is faster on real-world issues: a median task takes 3m 31s 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 $0.146).
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; Kimi K3 256K: real-world issues usage 23% to 21% of the weekly limit, spec planning D+ to C-, spec planning usage 11% to 10% of the weekly limit, vibe coding usage 3% to 2.6% of the weekly limit.
| Dimension | Gemini 3.1 Pro | Kimi K3 256K | Advantage |
|---|---|---|---|
| Capability | 53% | 60% | +7% (Kimi K3 256K leads) |
| Median task time | 4m 53s | 3m 31s | 1m 22s faster (Kimi K3 256K leads) |
| Approx. task cost | $0.045 / task | $0.126 / task | $0.080 / 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. Kimi K3 256K: 104.0% of Kimi Allegretto (104.0% / 5h, 21.0% / 1w) per run. Its weekly limit holds about 5 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 | Kimi K3 256K | Advantage |
|---|---|---|---|
| Capability | 21% | 56% | +35% (Kimi K3 256K leads) |
| Median task time | 1m 46s | 5m 26s | 3m 40s faster (Gemini 3.1 Pro leads) |
| Approx. task cost | $0.013 / task | $0.224 / task | $0.212 / 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. Kimi K3 256K: 52.0% of Kimi Allegretto (52.0% / 5h, 10.0% / 1w) per run. Its weekly limit holds about 5 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 | Kimi K3 256K | Advantage |
|---|---|---|---|
| Capability | 27% | 34% | +7% (Kimi K3 256K leads) |
| Median task time | 4m 38s | 7m 33s | 2m 55s faster (Gemini 3.1 Pro leads) |
| Approx. task cost | $0.034 / task | $0.233 / task | $0.199 / 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. Kimi K3 256K: 13.2% of Kimi Allegretto (13.2% / 5h, 2.6% / 1w) per good solve. Its weekly limit holds about 5 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 Kimi K3 256K?
Kimi K3 256K clears higher: tier 4 of 5 versus tier 3 for Gemini 3.1 Pro 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 Kimi K3 256K?
Gemini 3.1 Pro used 15.9% of Google AI Pro's weekly limit per pass, $0.038 per task at the listed price. Kimi K3 256K used 31% of Kimi Allegretto's weekly limit per pass, $0.146 per task at the listed price. Per task, Gemini 3.1 Pro is about 3.8x cheaper ($0.038 vs $0.146).