Claude Opus 5.5 vs GPT-5.6 Sol
GPT-5.6 Sol was superseded by GPT-6.1 Sol. The grades below are the last ones measured, so read them as history rather than as this week's board. See the current roster.
Claude Opus 5.5 leads overall, B- to C-. Claude Opus 5.5 is about 1.5x cheaper per task. By suite, Claude Opus 5.5 takes real-world issues (C+ to C-) and spec planning is even at C+. The data gives no reason to pick GPT-5.6 Sol over Claude Opus 5.5 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 Sol vs Claude Opus 5.5
Claude Opus 5.5 leads overall, B- to C-. By suite: Claude Opus 5.5 takes real-world issues, C+ to C- (73% vs 60% capability); spec planning is even at C+ (73% vs 68% capability); Claude Opus 5.5 takes vibe coding, B+ to D+ (90% vs 51% capability). Claude Opus 5.5 used 2% of Claude Max 5x's weekly limit per pass, $0.024 per task at the listed price. GPT-5.6 Sol used 3% of ChatGPT Pro 5x's weekly limit per pass, $0.036 per task at the listed price. Per task, Claude Opus 5.5 is about 1.5x cheaper ($0.024 vs $0.036). Claude Opus 5.5 is faster on real-world issues: a median task takes 1m 17s against 3m 13s. Both finished every task on it. The data gives no reason to pick GPT-5.6 Sol over Claude Opus 5.5 this week.
Changed since the previous graded week: Claude Opus 5.5: real-world issues C- to C+, vibe coding B to B+; GPT-5.6 Sol: vibe coding C- to D+.
| Dimension | Claude Opus 5.5 | GPT-5.6 Sol | Advantage |
|---|---|---|---|
| Capability | 73% | 60% | +13% (Claude Opus 5.5 leads) |
| Median task time | 1m 17s | 3m 13s | 1m 57s faster (Claude Opus 5.5 leads) |
| Approx. task cost | $0.015 / task | $0.031 / task | $0.015 / task lower (Claude Opus 5.5 leads) |
Claude Opus 5.5: 11.0% of Claude Max 5x (11.0% / 5h, 1.0% / 1w) per run. Its weekly limit holds about 13.8 of the week's 33.6 5h windows. GPT-5.6 Sol: 2.0% of ChatGPT Pro 5x (2.0% / 1w) per run. Each figure is a share of that agent's own plan, so there is no delta to draw.
| Dimension | Claude Opus 5.5 | GPT-5.6 Sol | Advantage |
|---|---|---|---|
| Capability | 73% | 68% | +4% (Claude Opus 5.5 leads) |
| Median task time | 4m 17s | 6m 0s | 1m 43s faster (Claude Opus 5.5 leads) |
| Approx. task cost | $0.057 / task | $0.057 / task | Even |
Claude Opus 5.5: 6.0% of Claude Max 5x (6.0% / 5h, 1.0% / 1w) per run. Its weekly limit holds about 13.8 of the week's 33.6 5h windows. GPT-5.6 Sol: 1.0% of ChatGPT Pro 5x (1.0% / 1w) per run. Each figure is a share of that agent's own plan, so there is no delta to draw.
| Dimension | Claude Opus 5.5 | GPT-5.6 Sol | Advantage |
|---|---|---|---|
| Capability | 90% | 51% | +39% (Claude Opus 5.5 leads) |
| Median task time | 2m 44s | 3m 56s | 1m 12s faster (Claude Opus 5.5 leads) |
| Approx. task cost | $0.007 / task | $0.092 / task | $0.085 / task lower (Claude Opus 5.5 leads) |
Claude Opus 5.5: 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-5.6 Sol: 0.4% of ChatGPT Pro 5x (0.4% / 1w) 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, Claude Opus 5.5 or GPT-5.6 Sol?
Both clear tier 4 of 5, but Claude Opus 5.5 scores higher on capability: 73% versus 60% on real-world@v3, our private suite of real-world coding problems. Latest measurement 2026-09-28.
Which is cheaper per task, Claude Opus 5.5 or GPT-5.6 Sol?
Claude Opus 5.5 used 2% of Claude Max 5x's weekly limit per pass, $0.024 per task at the listed price. GPT-5.6 Sol used 3% of ChatGPT Pro 5x's weekly limit per pass, $0.036 per task at the listed price. Per task, Claude Opus 5.5 is about 1.5x cheaper ($0.024 vs $0.036).
What do Claude Opus 5.5 and GPT-5.6 Sol cost a month?
Claude Opus 5.5 runs on Claude Max 5x at $100/month (public price as of 2026-07-27). GPT-5.6 Sol runs on ChatGPT Pro 5x at $100/month (public price as of 2026-09-05).