Claude Opus 5.5 vs Claude Sonnet 5
Claude Opus 5.5 leads overall, C+ to D. The two cost about the same per task. By suite, Claude Opus 5.5 takes real-world issues (C- to D+) and spec planning (C+ to D). The data gives no reason to pick Claude Sonnet 5 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: Claude Sonnet 5 vs Claude Opus 5.5
Claude Opus 5.5 leads overall, C+ to D. By suite: Claude Opus 5.5 takes real-world issues, C- to D+ (60% vs 50% capability); Claude Opus 5.5 takes spec planning, C+ to D (69% vs 42% capability); Claude Opus 5.5 takes vibe coding, B to D+ (85% vs 51% capability). Claude Opus 5.5 used 1% of Claude Max 5x's weekly limit per pass, $0.012 per task at the listed price. Claude Sonnet 5 used 1% of Claude Max 5x's weekly limit per pass, $0.012 per task at the listed price. Per task the two cost about the same ($0.012 vs $0.012). Claude Opus 5.5 is faster on real-world issues: a median task takes 2m 18s against 2m 55s. Both finished every task on it. The data gives no reason to pick Claude Sonnet 5 over Claude Opus 5.5 this week.
Changed since W32: Claude Sonnet 5: real-world issues F to D+.
| Dimension | Claude Opus 5.5 | Claude Sonnet 5 | Advantage |
|---|---|---|---|
| Capability | 60% | 50% | +10% (Claude Opus 5.5 leads) |
| Median task time | 2m 18s | 2m 55s | 37s faster (Claude Opus 5.5 leads) |
| Approx. task cost | $0.015 / task | $0.015 / task | Even |
Claude Opus 5.5: 16.0% of Claude Max 5x (16.0% / 5h, 1.0% / 1w) per run. Its weekly limit holds about 14.6 of the week's 33.6 5h windows. Claude Sonnet 5: 16.0% of Claude Max 5x (16.0% / 5h, 1.0% / 1w) per run. Its weekly limit holds about 14.6 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.
Work per window: Claude Opus 5.5 913 vs Claude Sonnet 5 913 suite runs per month (Claude Opus 5.5 leads); per plan-dollar: 9.13 vs 9.13 (Claude Opus 5.5 leads). Work figures compare outputs, so unlike quota shares they are comparable across plans.
| Dimension | Claude Opus 5.5 | Claude Sonnet 5 | Advantage |
|---|---|---|---|
| Capability | 69% | 42% | +27% (Claude Opus 5.5 leads) |
| Median task time | 3m 45s | 4m 20s | 34s faster (Claude Opus 5.5 leads) |
| Approx. task cost | $0.010 / task | $0.010 / task | Even |
Claude Opus 5.5: 6.0% of Claude Max 5x (6.0% / 5h) per run. Its weekly limit holds about 14.6 of the week's 33.6 5h windows. Claude Sonnet 5: 6.0% of Claude Max 5x (6.0% / 5h) per run. Its weekly limit holds about 14.6 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.
Work per window: Claude Opus 5.5 2435 vs Claude Sonnet 5 2435 suite runs per month (Claude Opus 5.5 leads); per plan-dollar: 24.35 vs 24.35 (Claude Opus 5.5 leads). Work figures compare outputs, so unlike quota shares they are comparable across plans.
| Dimension | Claude Opus 5.5 | Claude Sonnet 5 | Advantage |
|---|---|---|---|
| Capability | 85% | 51% | +34% (Claude Opus 5.5 leads) |
| Median task time | 2m 27s | 4m 26s | 1m 59s faster (Claude Opus 5.5 leads) |
| Approx. task cost | $0.046 / task | $0.016 / task | $0.030 / task lower (Claude Sonnet 5 leads) |
Claude Opus 5.5: 0.8% of Claude Max 5x (0.8% / 5h, 0.2% / 1w) per good solve. Its weekly limit holds about 14.6 of the week's 33.6 5h windows. Claude Sonnet 5: 2.4% of Claude Max 5x (2.4% / 5h) per good solve. Its weekly limit holds about 14.6 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.
Work per window: Claude Opus 5.5 18263 vs Claude Sonnet 5 6088 good solves per month (Claude Opus 5.5 leads); per plan-dollar: 182.63 vs 60.88 (Claude Opus 5.5 leads). Work figures compare outputs, so unlike quota shares they are comparable across plans.
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 Claude Sonnet 5?
Claude Opus 5.5 clears higher: tier 4 of 5 versus tier 2 for Claude Sonnet 5 on real-world@v3, our private suite of real-world coding problems. Latest measurement 2026-09-23.
Which is cheaper per task, Claude Opus 5.5 or Claude Sonnet 5?
Claude Opus 5.5 used 1% of Claude Max 5x's weekly limit per pass, $0.012 per task at the listed price. Claude Sonnet 5 used 1% of Claude Max 5x's weekly limit per pass, $0.012 per task at the listed price. Per task the two cost about the same ($0.012 vs $0.012).
Which gives more coding work per dollar, Claude Opus 5.5 or Claude Sonnet 5?
Claude Opus 5.5 delivers more benchmark work per subscription dollar: 9.13 suite runs per plan-dollar versus 9.13 for Claude Sonnet 5 (at $100/month priced 2026-07-27, and $100/month priced 2026-07-20). Work figures compare outputs, so unlike raw quota shares they are comparable across plans.
What do Claude Opus 5.5 and Claude Sonnet 5 cost a month?
Claude Opus 5.5 runs on Claude Max 5x at $100/month (public price as of 2026-07-27). Claude Sonnet 5 runs on Claude Max 5x at $100/month (public price as of 2026-07-20).