Claude Sonnet 5.5 vs Composer 2.5
Claude Sonnet 5.5 leads overall, C- to D. Claude Sonnet 5.5 is about 7.4x cheaper per task. By suite, real-world issues is even at C- and Claude Sonnet 5.5 takes spec planning (C+ to D). The data gives no reason to pick Composer 2.5 over Claude Sonnet 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: Composer 2.5 vs Claude Sonnet 5.5
Claude Sonnet 5.5 leads overall, C- to D. By suite: real-world issues is even at C- (60% vs 57% capability); Claude Sonnet 5.5 takes spec planning, C+ to D (74% vs 48% capability); Claude Sonnet 5.5 takes vibe coding, D+ to F (48% vs 23% capability). Claude Sonnet 5.5 used <1% of Claude Max 5x's weekly limit per pass, $0.003 per task at the listed price. Composer 2.5 used 2.0% of Cursor Pro's monthly limit per pass, $0.021 per task at the listed price. Per task, Claude Sonnet 5.5 is about 7.4x cheaper ($0.003 vs $0.021). Claude Sonnet 5.5 is faster on real-world issues: a median task takes 37s against 1m 34s. Both finished every task on it. The data gives no reason to pick Composer 2.5 over Claude Sonnet 5.5 this week.
Changed since W39: Composer 2.5: real-world issues D+ to C-.
| Dimension | Claude Sonnet 5.5 | Composer 2.5 | Advantage |
|---|---|---|---|
| Capability | 60% | 57% | +3% (Claude Sonnet 5.5 leads) |
| Median task time | 37s | 1m 34s | 57s faster (Claude Sonnet 5.5 leads) |
| Approx. task cost | $0.002 / task | $0.021 / task | $0.019 / 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. Composer 2.5: 1.6% of Cursor Pro (1.6% / 1m) per run. Each figure is a share of that agent's own plan, so there is no delta to draw.
Work per window: Claude Sonnet 5.5 3653 vs Composer 2.5 63 suite runs per month (Claude Sonnet 5.5 leads); per plan-dollar: 36.52 vs 3.15 (Claude Sonnet 5.5 leads). Work figures compare outputs, so unlike quota shares they are comparable across plans.
| Dimension | Claude Sonnet 5.5 | Composer 2.5 | Advantage |
|---|---|---|---|
| Capability | 74% | 48% | +26% (Claude Sonnet 5.5 leads) |
| Median task time | 3m 25s | 1m 8s | 2m 17s faster (Composer 2.5 leads) |
| Approx. task cost | $0.007 / task | $0.022 / task | $0.015 / 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. Composer 2.5: 0.4% of Cursor Pro (0.4% / 1m) per run. Each figure is a share of that agent's own plan, so there is no delta to draw.
Work per window: Claude Sonnet 5.5 3653 vs Composer 2.5 225 suite runs per month (Claude Sonnet 5.5 leads); per plan-dollar: 36.52 vs 11.23 (Claude Sonnet 5.5 leads). Work figures compare outputs, so unlike quota shares they are comparable across plans.
| Dimension | Claude Sonnet 5.5 | Composer 2.5 | Advantage |
|---|---|---|---|
| Capability | 48% | 23% | +26% (Claude Sonnet 5.5 leads) |
| Median task time | 56s | 1m 37s | 40s faster (Claude Sonnet 5.5 leads) |
| Approx. task cost | $0.001 / task | $0.022 / task | $0.020 / 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. Composer 2.5: 0.1% of Cursor Pro (0.1% / 1m) per good solve. Each figure is a share of that agent's own plan, so there is no delta to draw.
Work per window: Claude Sonnet 5.5 73050 vs Composer 2.5 920 good solves per month (Claude Sonnet 5.5 leads); per plan-dollar: 730.50 vs 46.02 (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 Sonnet 5.5 or Composer 2.5?
Claude Sonnet 5.5 clears higher: tier 4 of 5 versus tier 1 for Composer 2.5 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 Composer 2.5?
Claude Sonnet 5.5 used <1% of Claude Max 5x's weekly limit per pass, $0.003 per task at the listed price. Composer 2.5 used 2.0% of Cursor Pro's monthly limit per pass, $0.021 per task at the listed price. Per task, Claude Sonnet 5.5 is about 7.4x cheaper ($0.003 vs $0.021).
Which gives more coding work per dollar, Claude Sonnet 5.5 or Composer 2.5?
Claude Sonnet 5.5 delivers more benchmark work per subscription dollar: 36.52 suite runs per plan-dollar versus 3.15 for Composer 2.5 (at $100/month priced 2026-07-20, and $20/month priced 2026-07-20). Work figures compare outputs, so unlike raw quota shares they are comparable across plans.
What do Claude Sonnet 5.5 and Composer 2.5 cost a month?
Claude Sonnet 5.5 runs on Claude Max 5x at $100/month (public price as of 2026-07-20). Composer 2.5 runs on Cursor Pro at $20/month (public price as of 2026-07-20).