Claude Opus 5.5 vs Claude Sonnet 5.5
Claude Opus 5.5 leads overall, B- to C-. Claude Sonnet 5.5 is about 8.4x cheaper per task. By suite, Claude Opus 5.5 takes real-world issues (C+ to C-) and spec planning is even at C+. Take Claude Sonnet 5.5 anyway when you want the side that is cheaper per task and faster on real-world issues.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 5.5 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 60% capability); spec planning is even at C+ (73% vs 74% capability); Claude Opus 5.5 takes vibe coding, B+ to D+ (90% vs 48% 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 5.5 used <1% of Claude Max 5x's weekly limit per pass, $0.003 per task at the listed price. Per task, Claude Sonnet 5.5 is about 8.4x cheaper ($0.003 vs $0.024). Claude Sonnet 5.5 is faster on real-world issues: a median task takes 37s against 1m 17s. Both finished every task on it. Reasons to pick Claude Sonnet 5.5 anyway: it is cheaper per task ($0.003 vs $0.024) and it is faster on real-world issues (37s vs 1m 17s median).
Changed since W39: Claude Opus 5.5: real-world issues C- to C+, vibe coding B to B+.
| Dimension | Claude Opus 5.5 | Claude Sonnet 5.5 | Advantage |
|---|---|---|---|
| Capability | 73% | 60% | +13% (Claude Opus 5.5 leads) |
| Median task time | 1m 17s | 37s | 39s faster (Claude Sonnet 5.5 leads) |
| Approx. task cost | $0.015 / task | $0.002 / task | $0.014 / task lower (Claude Sonnet 5.5 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. 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. 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 5.5 3653 suite runs per month (Claude Sonnet 5.5 leads); per plan-dollar: 13.28 vs 36.52 (Claude Sonnet 5.5 leads). Work figures compare outputs, so unlike quota shares they are comparable across plans.
| Dimension | Claude Opus 5.5 | Claude Sonnet 5.5 | Advantage |
|---|---|---|---|
| Capability | 73% | 74% | +2% (Claude Sonnet 5.5 leads) |
| Median task time | 4m 17s | 3m 25s | 52s faster (Claude Sonnet 5.5 leads) |
| Approx. task cost | $0.057 / task | $0.007 / task | $0.051 / task lower (Claude Sonnet 5.5 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. 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. 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 5.5 3653 suite runs per month (Claude Sonnet 5.5 leads); per plan-dollar: 24.35 vs 36.52 (Claude Sonnet 5.5 leads). Work figures compare outputs, so unlike quota shares they are comparable across plans.
| Dimension | Claude Opus 5.5 | Claude Sonnet 5.5 | Advantage |
|---|---|---|---|
| Capability | 90% | 48% | +41% (Claude Opus 5.5 leads) |
| Median task time | 2m 44s | 56s | 1m 48s faster (Claude Sonnet 5.5 leads) |
| Approx. task cost | $0.007 / task | $0.001 / task | $0.005 / task lower (Claude Sonnet 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. 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. 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 5.5 73050 good solves per month (Claude Sonnet 5.5 leads); per plan-dollar: 146.10 vs 730.50 (Claude Sonnet 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 5.5?
Both clear tier 4 of 5, but Claude Opus 5.5 scores higher on capability: 73% versus 60% 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 5.5?
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 5.5 used <1% of Claude Max 5x's weekly limit per pass, $0.003 per task at the listed price. Per task, Claude Sonnet 5.5 is about 8.4x cheaper ($0.003 vs $0.024).
Which gives more coding work per dollar, Claude Opus 5.5 or Claude Sonnet 5.5?
Claude Sonnet 5.5 delivers more benchmark work per subscription dollar: 36.52 suite runs per plan-dollar versus 13.28 for Claude Opus 5.5 (at $100/month priced 2026-07-20, and $100/month priced 2026-07-27). Work figures compare outputs, so unlike raw quota shares they are comparable across plans.
What do Claude Opus 5.5 and Claude Sonnet 5.5 cost a month?
Claude Opus 5.5 runs on Claude Max 5x at $100/month (public price as of 2026-07-27). Claude Sonnet 5.5 runs on Claude Max 5x at $100/month (public price as of 2026-07-20).