Claude Opus 5 vs Claude Sonnet 5.5
Claude Opus 5 was superseded by Claude Opus 5.5. 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 leads overall, C to C-. Claude Sonnet 5.5 is about 8.4x cheaper per task. By suite, real-world issues is even at C- and Claude Sonnet 5.5 takes spec planning (C+ to C). Take Claude Sonnet 5.5 anyway when you want the side that is cheaper per task, faster on real-world issues and ahead on spec planning.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
Claude Opus 5 leads overall, C to C-. By suite: real-world issues is even at C- (57% vs 60% capability); Claude Sonnet 5.5 takes spec planning, C+ to C (74% vs 66% capability); Claude Opus 5 takes vibe coding, C+ to D+ (72% vs 48% capability). Claude Opus 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 56s. Both finished every task on it. Reasons to pick Claude Sonnet 5.5 anyway: it is cheaper per task ($0.003 vs $0.024), it is faster on real-world issues (37s vs 1m 56s median) and it leads on spec planning (C+ to C).
Changed since W32: Claude Opus 5: real-world issues usage 3% to 1% of the weekly limit.
| Dimension | Claude Opus 5 | Claude Sonnet 5.5 | Advantage |
|---|---|---|---|
| Capability | 57% | 60% | +3% (Claude Sonnet 5.5 leads) |
| Median task time | 1m 56s | 37s | 1m 19s 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: 21.0% of Claude Max 5x (21.0% / 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 5 696 vs Claude Sonnet 5.5 3653 suite runs per month (Claude Sonnet 5.5 leads); per plan-dollar: 6.96 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 | Claude Sonnet 5.5 | Advantage |
|---|---|---|---|
| Capability | 66% | 74% | +9% (Claude Sonnet 5.5 leads) |
| Median task time | 2m 9s | 3m 25s | 1m 16s faster (Claude Opus 5 leads) |
| Approx. task cost | $0.057 / task | $0.007 / task | $0.051 / task lower (Claude Sonnet 5.5 leads) |
Claude Opus 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 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 | Claude Sonnet 5.5 | Advantage |
|---|---|---|---|
| Capability | 72% | 48% | +23% (Claude Opus 5 leads) |
| Median task time | 2m 51s | 56s | 1m 55s faster (Claude Sonnet 5.5 leads) |
| Approx. task cost | $0.011 / task | $0.001 / task | $0.010 / task lower (Claude Sonnet 5.5 leads) |
Claude Opus 5: 1.6% of Claude Max 5x (1.6% / 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 9131 vs Claude Sonnet 5.5 73050 good solves per month (Claude Sonnet 5.5 leads); per plan-dollar: 91.31 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 or Claude Sonnet 5.5?
Claude Sonnet 5.5 clears higher: tier 4 of 5 versus tier 2 for Claude Opus 5 on real-world@v3, our private suite of real-world coding problems. Latest measurement 2026-09-21.
Which is cheaper per task, Claude Opus 5 or Claude Sonnet 5.5?
Claude Opus 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 or Claude Sonnet 5.5?
Claude Sonnet 5.5 delivers more benchmark work per subscription dollar: 36.52 suite runs per plan-dollar versus 6.96 for Claude Opus 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 and Claude Sonnet 5.5 cost a month?
Claude Opus 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).