GPT-6 Astra vs Kimi K3 256K
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.
| Dimension | GPT-6 Astra | Kimi K3 256K | Advantage |
|---|---|---|---|
| Capability | 57% | 57% | Even |
| Median task time | 1m 56s | 3m 34s | 1m 38s faster (GPT-6 Astra leads) |
| Approx. task cost | $0.046 / task | $0.025 / task | $0.021 / task lower (Kimi K3 256K leads) |
GPT-6 Astra: 3.0% of ChatGPT Pro $100 (3.0% / 1w) per run. Kimi K3 256K: 140.0% of Kimi Allegretto (140.0% / 5h, 28.0% / 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 | GPT-6 Astra | Kimi K3 256K | Advantage |
|---|---|---|---|
| Capability | 74% | 41% | +32% (GPT-6 Astra leads) |
| Median task time | 4m 0s | 6m 34s | 2m 34s faster (GPT-6 Astra leads) |
| Approx. task cost | $0.057 / task | $0.031 / task | $0.027 / task lower (Kimi K3 256K leads) |
GPT-6 Astra: 1.0% of ChatGPT Pro $100 (1.0% / 1w) per run. Kimi K3 256K: 46.0% of Kimi Allegretto (46.0% / 5h, 9.0% / 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 | GPT-6 Astra | Kimi K3 256K | Advantage |
|---|---|---|---|
| Capability | 61% | 55% | +6% (GPT-6 Astra leads) |
| Median task time | 2m 54s | 6m 31s | 3m 37s faster (GPT-6 Astra leads) |
| Approx. task cost | $0.046 / task | $0.029 / task | $0.017 / task lower (Kimi K3 256K leads) |
GPT-6 Astra: 0.2% of ChatGPT Pro $100 (0.2% / 1w) per good solve. Kimi K3 256K: 11.0% of Kimi Allegretto (11.0% / 5h, 2.4% / 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, GPT-6 Astra or Kimi K3 256K?
They are even on our ladder: both clear tier 2 of 5 at 57% capability on real-world@v3, our private suite of real-world coding problems. Latest measurement 2026-09-05.
How much do GPT-6 Astra and Kimi K3 256K cost?
GPT-6 Astra runs on ChatGPT Pro $100 at $100/month (public price as of 2026-09-05). Kimi K3 256K runs on Kimi Allegretto at $39/month (public price as of 2026-07-20).