Claude Sonnet 5.5 vs GPT-5.6 Sol
GPT-5.6 Sol was superseded by GPT-6 Sol.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.
Both grade C- overall. Claude Sonnet 5.5 is about 13x cheaper per task. By suite, real-world issues is even at C- and spec planning is even at 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-5.6 Sol vs Claude Sonnet 5.5
Both grade C- overall. By suite: real-world issues is even at C- (60% vs 60% capability); spec planning is even at C+ (74% vs 68% capability); vibe coding is even at D+ (48% vs 51% 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-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 Sonnet 5.5 is about 13x cheaper ($0.003 vs $0.036). Claude Sonnet 5.5 is faster on real-world issues: a median task takes 37s against 3m 13s. Both finished every task on it.
Changed since W38: GPT-5.6 Sol: vibe coding C- to D+.
| Dimension | Claude Sonnet 5.5 | GPT-5.6 Sol | Advantage |
|---|---|---|---|
| Capability | 60% | 60% | Even |
| Median task time | 37s | 3m 13s | 2m 36s faster (Claude Sonnet 5.5 leads) |
| Approx. task cost | $0.002 / task | $0.031 / task | $0.029 / 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-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 Sonnet 5.5 | GPT-5.6 Sol | Advantage |
|---|---|---|---|
| Capability | 74% | 68% | +6% (Claude Sonnet 5.5 leads) |
| Median task time | 3m 25s | 6m 0s | 2m 35s faster (Claude Sonnet 5.5 leads) |
| Approx. task cost | $0.007 / task | $0.057 / task | $0.051 / 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-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 Sonnet 5.5 | GPT-5.6 Sol | Advantage |
|---|---|---|---|
| Capability | 48% | 51% | +3% (GPT-5.6 Sol leads) |
| Median task time | 56s | 3m 56s | 3m 0s faster (Claude Sonnet 5.5 leads) |
| Approx. task cost | $0.001 / task | $0.092 / task | $0.091 / 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-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 Sonnet 5.5 or GPT-5.6 Sol?
They are even on our ladder: both clear tier 4 of 5 at 60% capability 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-5.6 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-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 Sonnet 5.5 is about 13x cheaper ($0.003 vs $0.036).
What do Claude Sonnet 5.5 and GPT-5.6 Sol cost a month?
Claude Sonnet 5.5 runs on Claude Max 5x at $100/month (public price as of 2026-07-20). GPT-5.6 Sol runs on ChatGPT Pro 5x at $100/month (public price as of 2026-09-05).