Claude Sonnet 5.5 vs GPT-6 Sol
Both grade C- overall. Claude Sonnet 5.5 is about 5.9x cheaper per task. By suite, real-world issues is even at C- and Claude Sonnet 5.5 takes spec planning (C+ to C-). Both agents run the same private suite cut headless through their own tools, each on its own subscription.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 Sol vs Claude Sonnet 5.5
Both grade C- overall. By suite: real-world issues is even at C- (60% vs 55% capability); Claude Sonnet 5.5 takes spec planning, C+ to C- (74% vs 60% capability); GPT-6 Sol takes vibe coding, C- to D+ (61% vs 48% capability). Claude Sonnet 5.5 used <1% of Claude Max 5x's weekly limit per pass, $0.003 per task at the listed price. GPT-6 Sol used 7% of ChatGPT Plus's weekly limit per pass, $0.017 per task at the listed price; at the ~$100 tier the board defaults to that is an estimated ~1.4% of ChatGPT Pro 5x's weekly limit (est, about $0.017 per task). Per task, Claude Sonnet 5.5 is about 5.9x cheaper ($0.003 vs $0.017). Claude Sonnet 5.5 is faster on real-world issues: a median task takes 37s against 1m 41s. Both finished every task on it.
Changed since W39: GPT-6 Sol: real-world issues D- to C-, real-world issues usage 4% to 5% of the weekly limit, spec planning C to C-, spec planning usage 1% to 2% of the weekly limit, vibe coding D+ to C-.
| Dimension | Claude Sonnet 5.5 | GPT-6 Sol | Advantage |
|---|---|---|---|
| Capability | 60% | 55% | +5% (Claude Sonnet 5.5 leads) |
| Median task time | 37s | 1m 41s | 1m 4s faster (Claude Sonnet 5.5 leads) |
| Approx. task cost | $0.002 / task | $0.015 / task | $0.014 / task lower (Claude Sonnet 5.5 leads) |
Claude Sonnet 5.5: 4.0% of Claude Max 5x (4.0% / 5h) per run. Its weekly limit holds about 13.8 of the week's 33.6 5h windows. GPT-6 Sol: 5.0% of ChatGPT Plus (35.0% / 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 5.5 | GPT-6 Sol | Advantage |
|---|---|---|---|
| Capability | 74% | 60% | +14% (Claude Sonnet 5.5 leads) |
| Median task time | 3m 25s | 2m 58s | 27s faster (GPT-6 Sol leads) |
| Approx. task cost | $0.007 / task | $0.023 / task | $0.016 / task lower (Claude Sonnet 5.5 leads) |
Claude Sonnet 5.5: 4.0% of Claude Max 5x (4.0% / 5h) per run. Its weekly limit holds about 13.8 of the week's 33.6 5h windows. GPT-6 Sol: 2.0% of ChatGPT Plus (10.0% / 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 Sonnet 5.5 | GPT-6 Sol | Advantage |
|---|---|---|---|
| Capability | 48% | 61% | +13% (GPT-6 Sol leads) |
| Median task time | 56s | 2m 44s | 1m 48s faster (Claude Sonnet 5.5 leads) |
| Approx. task cost | $0.001 / task | $0.018 / task | $0.017 / task lower (Claude Sonnet 5.5 leads) |
Claude Sonnet 5.5: 0.2% of Claude Max 5x (0.2% / 5h) per good solve. Its weekly limit holds about 13.8 of the week's 33.6 5h windows. GPT-6 Sol: 0.4% of ChatGPT Plus (1.8% / 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 Sonnet 5.5 or GPT-6 Sol?
Claude Sonnet 5.5 clears higher: tier 4 of 5 versus tier 1 for GPT-6 Sol on real-world@v3, our private suite of real-world coding problems. Latest measurement 2026-09-28.
Which is cheaper per task, Claude Sonnet 5.5 or GPT-6 Sol?
Claude Sonnet 5.5 used <1% of Claude Max 5x's weekly limit per pass, $0.003 per task at the listed price. GPT-6 Sol used 7% of ChatGPT Plus's weekly limit per pass, $0.017 per task at the listed price; at the ~$100 tier the board defaults to that is an estimated ~1.4% of ChatGPT Pro 5x's weekly limit (est, about $0.017 per task). Per task, Claude Sonnet 5.5 is about 5.9x cheaper ($0.003 vs $0.017).
What do Claude Sonnet 5.5 and GPT-6 Sol cost a month?
Claude Sonnet 5.5 runs on Claude Max 5x at $100/month (public price as of 2026-07-20). GPT-6 Sol runs on ChatGPT Plus at $20/month (public price as of 2026-07-20).