Claude Haiku 4.5 vs Claude Sonnet 5.5
Claude Sonnet 5.5 leads overall, C- to F. Claude Sonnet 5.5 is about 4.2x cheaper per task. By suite, Claude Sonnet 5.5 takes real-world issues (C- to D-) and spec planning (C+ to F). The data gives no reason to pick Claude Haiku 4.5 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: Claude Sonnet 5.5 vs Claude Haiku 4.5
Claude Sonnet 5.5 leads overall, C- to F. By suite: Claude Sonnet 5.5 takes real-world issues, C- to D- (60% vs 37% capability); Claude Sonnet 5.5 takes spec planning, C+ to F (74% vs 21% capability); Claude Sonnet 5.5 takes vibe coding, D+ to F (48% vs 22% capability). Claude Haiku 4.5 used 1% of Claude Max 5x's weekly limit per pass, $0.012 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 4.2x cheaper ($0.003 vs $0.012). Claude Sonnet 5.5 is faster on real-world issues: a median task takes 37s against 3m 8s. Both finished every task on it. The data gives no reason to pick Claude Haiku 4.5 over Claude Sonnet 5.5 this week.
Changed since W39: Claude Haiku 4.5: real-world issues D+ to D-.
| Dimension | Claude Haiku 4.5 | Claude Sonnet 5.5 | Advantage |
|---|---|---|---|
| Capability | 37% | 60% | +23% (Claude Sonnet 5.5 leads) |
| Median task time | 3m 8s | 37s | 2m 31s 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 Haiku 4.5: 8.0% of Claude Max 5x (8.0% / 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 Haiku 4.5 1826 vs Claude Sonnet 5.5 3653 suite runs per month (Claude Sonnet 5.5 leads); per plan-dollar: 18.26 vs 36.52 (Claude Sonnet 5.5 leads). Work figures compare outputs, so unlike quota shares they are comparable across plans.
| Dimension | Claude Haiku 4.5 | Claude Sonnet 5.5 | Advantage |
|---|---|---|---|
| Capability | 21% | 74% | +53% (Claude Sonnet 5.5 leads) |
| Median task time | 2m 8s | 3m 25s | 1m 17s faster (Claude Haiku 4.5 leads) |
| Approx. task cost | $0.002 / task | $0.007 / task | $0.005 / task lower (Claude Haiku 4.5 leads) |
Claude Haiku 4.5: 1.0% of Claude Max 5x (1.0% / 5h) 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 Haiku 4.5 14610 vs Claude Sonnet 5.5 3653 suite runs per month (Claude Haiku 4.5 leads); per plan-dollar: 146.10 vs 36.52 (Claude Haiku 4.5 leads). Work figures compare outputs, so unlike quota shares they are comparable across plans.
| Dimension | Claude Haiku 4.5 | Claude Sonnet 5.5 | Advantage |
|---|---|---|---|
| Capability | 22% | 48% | +26% (Claude Sonnet 5.5 leads) |
| Median task time | 4m 4s | 56s | 3m 7s faster (Claude Sonnet 5.5 leads) |
| Approx. task cost | $0.009 / task | $0.001 / task | $0.007 / task lower (Claude Sonnet 5.5 leads) |
Claude Haiku 4.5: 1.3% of Claude Max 5x (1.3% / 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 Haiku 4.5 11688 vs Claude Sonnet 5.5 73050 good solves per month (Claude Sonnet 5.5 leads); per plan-dollar: 116.88 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 Haiku 4.5 or Claude Sonnet 5.5?
Claude Sonnet 5.5 clears higher: tier 4 of 5 versus tier 2 for Claude Haiku 4.5 on real-world@v3, our private suite of real-world coding problems. Latest measurement 2026-09-28.
Which is cheaper per task, Claude Haiku 4.5 or Claude Sonnet 5.5?
Claude Haiku 4.5 used 1% of Claude Max 5x's weekly limit per pass, $0.012 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 4.2x cheaper ($0.003 vs $0.012).
Which gives more coding work per dollar, Claude Haiku 4.5 or Claude Sonnet 5.5?
Claude Sonnet 5.5 delivers more benchmark work per subscription dollar: 36.52 suite runs per plan-dollar versus 18.26 for Claude Haiku 4.5 (at $100/month priced 2026-07-20, and $100/month priced 2026-07-20). Work figures compare outputs, so unlike raw quota shares they are comparable across plans.
What do Claude Haiku 4.5 and Claude Sonnet 5.5 cost a month?
Claude Haiku 4.5 runs on Claude Max 5x at $100/month (public price as of 2026-07-20). Claude Sonnet 5.5 runs on Claude Max 5x at $100/month (public price as of 2026-07-20).