GPT-6 Astra vs Composer 2.5
GPT-6 Astra leads overall, C to D. Composer 2.5 is about 2.5x cheaper per task. By suite, Composer 2.5 takes real-world issues (C- to D) and GPT-6 Astra takes spec planning (C+ to D). Take Composer 2.5 anyway when you want the side that is cheaper per task, faster on real-world issues 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: Composer 2.5 vs GPT-6 Astra
GPT-6 Astra leads overall, C to D. By suite: Composer 2.5 takes real-world issues, C- to D (57% vs 43% capability); GPT-6 Astra takes spec planning, C+ to D (74% vs 48% capability); GPT-6 Astra takes vibe coding, C+ to F (74% vs 23% capability). 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). Composer 2.5 used 2.0% of Cursor Pro's monthly limit per pass, $0.021 per task at the listed price. Per task, Composer 2.5 is about 2.5x cheaper ($0.021 vs $0.053). Composer 2.5 is faster on real-world issues: a median task takes 1m 34s against 2m 13s. Both finished every task on it. Reasons to pick Composer 2.5 anyway: it is cheaper per task ($0.021 vs $0.053), it is faster on real-world issues (1m 34s vs 2m 13s median) and it leads on real-world issues (C- to D).
Changed since W39: GPT-6 Astra has one graded week under this version (W40); Composer 2.5: real-world issues D+ to C-.
| Dimension | GPT-6 Astra | Composer 2.5 | Advantage |
|---|---|---|---|
| Capability | 43% | 57% | +13% (Composer 2.5 leads) |
| Median task time | 2m 13s | 1m 34s | 39s faster (Composer 2.5 leads) |
| Approx. task cost | $0.052 / task | $0.021 / task | $0.031 / task lower (Composer 2.5 leads) |
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. Composer 2.5: 1.6% of Cursor Pro (1.6% / 1m) per run. Each figure is a share of that agent's own plan, so there is no delta to draw.
| Dimension | GPT-6 Astra | Composer 2.5 | Advantage |
|---|---|---|---|
| Capability | 74% | 48% | +26% (GPT-6 Astra leads) |
| Median task time | 3m 5s | 1m 8s | 1m 58s faster (Composer 2.5 leads) |
| Approx. task cost | $0.057 / task | $0.022 / task | $0.035 / task lower (Composer 2.5 leads) |
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. Composer 2.5: 0.4% of Cursor Pro (0.4% / 1m) per run. Each figure is a share of that agent's own plan, so there is no delta to draw.
| Dimension | GPT-6 Astra | Composer 2.5 | Advantage |
|---|---|---|---|
| Capability | 74% | 23% | +52% (GPT-6 Astra leads) |
| Median task time | 2m 40s | 1m 37s | 1m 3s faster (Composer 2.5 leads) |
| Approx. task cost | $0.046 / task | $0.022 / task | $0.024 / task lower (Composer 2.5 leads) |
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. Composer 2.5: 0.1% of Cursor Pro (0.1% / 1m) 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, GPT-6 Astra or Composer 2.5?
GPT-6 Astra clears higher: tier 2 of 5 versus tier 1 for Composer 2.5 on real-world@v3, our private suite of real-world coding problems. Latest measurement 2026-09-28.
Which is cheaper per task, GPT-6 Astra or Composer 2.5?
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). Composer 2.5 used 2.0% of Cursor Pro's monthly limit per pass, $0.021 per task at the listed price. Per task, Composer 2.5 is about 2.5x cheaper ($0.021 vs $0.053).
What do GPT-6 Astra and Composer 2.5 cost a month?
GPT-6 Astra runs on ChatGPT Plus at $20/month (public price as of 2026-07-20). Composer 2.5 runs on Cursor Pro at $20/month (public price as of 2026-07-20).