Claude Fable 5.1 vs Claude Haiku 4.5
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.
| Dimension | Claude Fable 5.1 | Claude Haiku 4.5 | Advantage |
|---|---|---|---|
| Capability | 73% | 62% | +12% (Claude Fable 5.1 leads) |
| Median task time | 1m 46s | 3m 31s | 1m 45s faster (Claude Fable 5.1 leads) |
| Approx. task cost | $0.026 / task | $0.004 / task | $0.022 / task lower (Claude Haiku 4.5 leads) |
Claude Fable 5.1: 28.0% of Claude Max 20x (28.0% / 5h, 5.0% / 1w) per run. Its weekly limit holds about 7.2 of the week's 33.6 5h windows. Claude Haiku 4.5: 4.0% of Claude Max 20x (4.0% / 5h, 1.0% / 1w) per run. Its weekly limit holds about 7.2 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 Fable 5.1 522 vs Claude Haiku 4.5 3653 suite runs per month (Claude Haiku 4.5 leads); per plan-dollar: 2.61 vs 18.26 (Claude Haiku 4.5 leads). Work figures compare outputs, so unlike quota shares they are comparable across plans.
| Dimension | Claude Fable 5.1 | Claude Haiku 4.5 | Advantage |
|---|---|---|---|
| Capability | 74% | 25% | +50% (Claude Fable 5.1 leads) |
| Median task time | 6m 51s | 2m 9s | 4m 42s faster (Claude Haiku 4.5 leads) |
| Approx. task cost | $0.051 / task | not measured | - |
Claude Fable 5.1: 15.0% of Claude Max 20x (15.0% / 5h, 2.0% / 1w) per run. Its weekly limit holds about 7.2 of the week's 33.6 5h windows. Claude Haiku 4.5: 0.0% of Claude Max 20x per run. Its weekly limit holds about 7.2 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.
| Dimension | Claude Fable 5.1 | Claude Haiku 4.5 | Advantage |
|---|---|---|---|
| Capability | 85% | 21% | +63% (Claude Fable 5.1 leads) |
| Median task time | 3m 48s | 4m 18s | 30s faster (Claude Fable 5.1 leads) |
| Approx. task cost | $0.025 / task | $0.003 / task | $0.022 / task lower (Claude Haiku 4.5 leads) |
Claude Fable 5.1: 1.8% of Claude Max 20x (1.8% / 5h, 0.2% / 1w) per good solve. Its weekly limit holds about 7.2 of the week's 33.6 5h windows. Claude Haiku 4.5: 0.2% of Claude Max 20x (0.2% / 5h) per good solve. Its weekly limit holds about 7.2 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 Fable 5.1 8117 vs Claude Haiku 4.5 73050 good solves per month (Claude Haiku 4.5 leads); per plan-dollar: 40.58 vs 365.25 (Claude Haiku 4.5 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 Fable 5.1 or Claude Haiku 4.5?
Claude Fable 5.1 clears higher: tier 4 of 5 versus tier 1 for Claude Haiku 4.5 on real-world@v3, our private suite of real-world coding problems. Latest measurement 2026-09-01.
Which gives more work per dollar, Claude Fable 5.1 or Claude Haiku 4.5?
Claude Haiku 4.5 delivers more benchmark work per subscription dollar: 18.26 suite runs per plan-dollar versus 2.61 for Claude Fable 5.1 (at $200/month priced 2026-08-05, and $200/month priced 2026-08-05). Work figures compare outputs, so unlike raw quota shares they are comparable across plans.
How much do Claude Fable 5.1 and Claude Haiku 4.5 cost?
Claude Fable 5.1 runs on Claude Max 20x at $200/month (public price as of 2026-08-05). Claude Haiku 4.5 runs on Claude Max 20x at $200/month (public price as of 2026-08-05).