Claude Opus 5.5 vs Claude Sonnet 5
Claude Sonnet 5 is no longer on the leaderboard. 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 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, B- to D. By suite: Claude Opus 5.5 takes real-world issues, C+ to D+ (73% vs 53% capability); Claude Opus 5.5 takes spec planning, C+ to D (73% vs 44% capability); Claude Opus 5.5 takes vibe coding, B+ to F (90% vs 31% capability). Claude Opus 5.5 used 2% of Claude Max 5x's weekly limit per pass, $0.024 per task at the listed price. Claude Sonnet 5 used 2% of Claude Max 5x's weekly limit per pass, $0.024 per task at the listed price. Per task the two cost about the same ($0.024 vs $0.024). Claude Opus 5.5 is faster on real-world issues: a median task takes 1m 17s against 3m 35s. 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 W39: Claude Opus 5.5: real-world issues C- to C+, vibe coding B to B+; Claude Sonnet 5: vibe coding D+ to F.
| Dimension | Claude Opus 5.5 | Claude Sonnet 5 | Advantage |
|---|---|---|---|
| Capability | 73% | 53% | +20% (Claude Opus 5.5 leads) |
| Median task time | 1m 17s | 3m 35s | 2m 19s faster (Claude Opus 5.5 leads) |
| Approx. task cost | $0.015 / task | $0.015 / task | Even |
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. Claude Sonnet 5: 12.0% of Claude Max 5x (12.0% / 5h, 1.0% / 1w) per run. Its weekly limit holds about 13.8 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 1328 vs Claude Sonnet 5 1218 suite runs per month (Claude Opus 5.5 leads); per plan-dollar: 13.28 vs 12.18 (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 | 73% | 44% | +29% (Claude Opus 5.5 leads) |
| Median task time | 4m 17s | 5m 12s | 55s 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. Claude Sonnet 5: 5.0% of Claude Max 5x (5.0% / 5h, 1.0% / 1w) per run. Its weekly limit holds about 13.8 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 2922 suite runs per month (Claude Sonnet 5 leads); per plan-dollar: 24.35 vs 29.22 (Claude Sonnet 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 | 90% | 31% | +59% (Claude Opus 5.5 leads) |
| Median task time | 2m 44s | 4m 31s | 1m 46s faster (Claude Opus 5.5 leads) |
| Approx. task cost | $0.007 / task | $0.007 / task | Even |
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. Claude Sonnet 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. 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 14610 vs Claude Sonnet 5 14610 good solves per month (Claude Opus 5.5 leads); per plan-dollar: 146.10 vs 146.10 (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 3 for Claude Sonnet 5 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 Claude Sonnet 5?
Claude Opus 5.5 used 2% of Claude Max 5x's weekly limit per pass, $0.024 per task at the listed price. Claude Sonnet 5 used 2% of Claude Max 5x's weekly limit per pass, $0.024 per task at the listed price. Per task the two cost about the same ($0.024 vs $0.024).
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: 13.28 suite runs per plan-dollar versus 12.18 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).