Claude Opus 5.5 vs GPT-6.1 Sol
Claude Opus 5.5 leads overall, B- to C. GPT-6.1 Sol is about 1.7x cheaper per task. By suite, Claude Opus 5.5 takes real-world issues (C+ to C-) and spec planning is even at C+. Take GPT-6.1 Sol 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: GPT-6.1 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 57% capability); spec planning is even at C+ (73% vs 73% capability); Claude Opus 5.5 takes vibe coding, B+ to C+ (90% vs 72% 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-6.1 Sol used 6% of ChatGPT Plus's weekly limit per pass, $0.015 per task at the listed price; at the ~$100 tier the board defaults to that is an estimated ~1.2% of ChatGPT Pro 5x's weekly limit (est, about $0.015 per task). Per task, GPT-6.1 Sol is about 1.7x cheaper ($0.015 vs $0.024). Claude Opus 5.5 is faster on real-world issues: a median task takes 1m 17s against 3m 26s. Both finished every task on it. Reasons to pick GPT-6.1 Sol anyway: it is cheaper per task ($0.015 vs $0.024).
Changed since W39: Claude Opus 5.5: real-world issues C- to C+, vibe coding B to B+; GPT-6.1 Sol has one graded week under this version (W40).
| Dimension | Claude Opus 5.5 | GPT-6.1 Sol | Advantage |
|---|---|---|---|
| Capability | 73% | 57% | +17% (Claude Opus 5.5 leads) |
| Median task time | 1m 17s | 3m 26s | 2m 10s faster (Claude Opus 5.5 leads) |
| Approx. task cost | $0.015 / task | $0.012 / task | $0.003 / task lower (GPT-6.1 Sol 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-6.1 Sol: 4.0% of ChatGPT Plus (28.0% / 5h, 4.0% / 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 Opus 5.5 | GPT-6.1 Sol | Advantage |
|---|---|---|---|
| Capability | 73% | 73% | +1% (GPT-6.1 Sol leads) |
| Median task time | 4m 17s | 6m 22s | 2m 5s faster (Claude Opus 5.5 leads) |
| Approx. task cost | $0.057 / task | $0.023 / task | $0.034 / task lower (GPT-6.1 Sol leads) |
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-6.1 Sol: 2.0% of ChatGPT Plus (9.0% / 5h, 2.0% / 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 Opus 5.5 | GPT-6.1 Sol | Advantage |
|---|---|---|---|
| Capability | 90% | 72% | +18% (Claude Opus 5.5 leads) |
| Median task time | 2m 44s | 4m 55s | 2m 10s faster (Claude Opus 5.5 leads) |
| Approx. task cost | $0.007 / task | $0.018 / task | $0.012 / 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-6.1 Sol: 0.4% of ChatGPT Plus (2.2% / 5h, 0.4% / 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 Opus 5.5 or GPT-6.1 Sol?
Claude Opus 5.5 clears higher: tier 4 of 5 versus tier 2 for GPT-6.1 Sol 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-6.1 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-6.1 Sol used 6% of ChatGPT Plus's weekly limit per pass, $0.015 per task at the listed price; at the ~$100 tier the board defaults to that is an estimated ~1.2% of ChatGPT Pro 5x's weekly limit (est, about $0.015 per task). Per task, GPT-6.1 Sol is about 1.7x cheaper ($0.015 vs $0.024).
What do Claude Opus 5.5 and GPT-6.1 Sol cost a month?
Claude Opus 5.5 runs on Claude Max 5x at $100/month (public price as of 2026-07-27). GPT-6.1 Sol runs on ChatGPT Plus at $20/month (public price as of 2026-07-20).