Claude Sonnet 5 vs GPT-6 Astra
Claude Sonnet 5 is no longer on the leaderboard. The grades below are the last ones measured, so read them as history rather than as this week's board. See the current roster.
GPT-6 Astra leads overall, C to D. Claude Sonnet 5 is about 2.2x cheaper per task. By suite, Claude Sonnet 5 takes real-world issues (D+ to D) and GPT-6 Astra takes spec planning (C+ to D). Take Claude Sonnet 5 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 Claude Sonnet 5
GPT-6 Astra leads overall, C to D. By suite: Claude Sonnet 5 takes real-world issues, D+ to D (53% vs 43% capability); GPT-6 Astra takes spec planning, C+ to D (74% vs 44% capability); GPT-6 Astra takes vibe coding, C+ to F (74% vs 31% capability). Claude Sonnet 5 used 2% of Claude Max 5x's weekly limit per pass, $0.024 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, Claude Sonnet 5 is about 2.2x cheaper ($0.024 vs $0.053). GPT-6 Astra is faster on real-world issues: a median task takes 2m 13s against 3m 35s. Both finished every task on it. Reasons to pick Claude Sonnet 5 anyway: it is cheaper per task ($0.024 vs $0.053) and it leads on real-world issues (D+ to D).
Changed since W39: Claude Sonnet 5: vibe coding D+ to F; GPT-6 Astra has one graded week under this version (W40).
| Dimension | Claude Sonnet 5 | GPT-6 Astra | Advantage |
|---|---|---|---|
| Capability | 53% | 43% | +10% (Claude Sonnet 5 leads) |
| Median task time | 3m 35s | 2m 13s | 1m 22s faster (GPT-6 Astra leads) |
| Approx. task cost | $0.015 / task | $0.052 / task | $0.037 / task lower (Claude Sonnet 5 leads) |
Claude Sonnet 5: 12.0% of Claude Max 5x (12.0% / 5h, 1.0% / 1w) per run. Its weekly limit holds about 13.8 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 | Claude Sonnet 5 | GPT-6 Astra | Advantage |
|---|---|---|---|
| Capability | 44% | 74% | +31% (GPT-6 Astra leads) |
| Median task time | 5m 12s | 3m 5s | 2m 6s faster (GPT-6 Astra leads) |
| Approx. task cost | $0.057 / task | $0.057 / task | Even |
Claude Sonnet 5: 5.0% of Claude Max 5x (5.0% / 5h, 1.0% / 1w) per run. Its weekly limit holds about 13.8 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 | Claude Sonnet 5 | GPT-6 Astra | Advantage |
|---|---|---|---|
| Capability | 31% | 74% | +43% (GPT-6 Astra leads) |
| Median task time | 4m 31s | 2m 40s | 1m 51s faster (GPT-6 Astra leads) |
| Approx. task cost | $0.007 / task | $0.046 / task | $0.039 / task lower (Claude Sonnet 5 leads) |
Claude Sonnet 5: 1.0% of Claude Max 5x (1.0% / 5h) per good solve. Its weekly limit holds about 13.8 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, Claude Sonnet 5 or GPT-6 Astra?
Claude Sonnet 5 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, Claude Sonnet 5 or GPT-6 Astra?
Claude Sonnet 5 used 2% of Claude Max 5x's weekly limit per pass, $0.024 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, Claude Sonnet 5 is about 2.2x cheaper ($0.024 vs $0.053).
What do Claude Sonnet 5 and GPT-6 Astra cost a month?
Claude Sonnet 5 runs on Claude Max 5x at $100/month (public price as of 2026-07-20). GPT-6 Astra runs on ChatGPT Plus at $20/month (public price as of 2026-07-20).