Model comparison
Claude 4 Sonnet vs Claude Fable 5
Head-to-head evidence from 13 shared benchmark results across 6 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.
Public leaderboard positions: Claude 4 Sonnet #158 (Supported); Claude Fable 5 #2 (Supported). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. Claude 4 Sonnet and Claude Fable 5 share 13 comparable benchmark results. 1 of 8 categories are comparable. 3 results are unique to Claude 4 Sonnet; 21 to Claude Fable 5.
Updated July 23, 2026- Shared results
- 13
- Claude 4 Sonnet only
- 3
- Claude Fable 5 only
- 21
- Comparable categories
- 1 / 8
Pick Claude Fable 5 if you want the stronger benchmark profile. Claude 4 Sonnet only becomes the better choice if you want the cheaper token bill or you would rather avoid the extra latency and token burn of a reasoning model.
Confidence note. This is a partial-evidence comparison with 13 shared benchmark results across 6 evidence categories; 1 of 8 categories currently have scoreable aggregates for both models. Treat the verdict as directional until coverage is more balanced.
Why this result
Claude Fable 5 is clearly ahead on the BenchAlign aggregate, 83.68 to 42.79. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
Claude Fable 5's sharpest advantage is in coding, where it averages 89.2 against 72.7. The single biggest benchmark swing on the page is SWE-bench Verified, 72.7% to 95%.
Claude Fable 5 is also the more expensive model on tokens at $10.00 input / $50.00 output per 1M tokens, versus $3.00 input / $15.00 output per 1M tokens for Claude 4 Sonnet. That is roughly 3.3x on output cost alone. Claude Fable 5 is the reasoning model in the pair, while Claude 4 Sonnet is not. That usually helps on harder chain-of-thought-heavy tests, but it can also mean more latency and more token spend in real use. Claude Fable 5 gives you the larger context window at 1M+, compared with 200K for Claude 4 Sonnet.
Category breakdown
Exact category averages are shown below. Not measured means BenchLM does not have enough sourced public coverage for that model and category.
| Category | Claude 4 Sonnet | Δ | Claude Fable 5 |
|---|---|---|---|
| Coding | Claude 4 Sonnet72.7 | Margin→ 16.5 | Claude Fable 589.2 |
| Agentic | Claude 4 SonnetNot measured | MarginNo overlap | Claude Fable 584.6 |
| Multimodal | Claude 4 SonnetNot measured | MarginNo overlap | Claude Fable 557.9 |
Decisive benchmark drivers
The largest measured benchmark gaps in this matchup, with exact reported values.
More
- Source ↗
SWE-bench Verified
CodingA 72.7%B 95%Winner: Claude Fable 5Δ 22.3SWE-bench Verified: Claude 4 Sonnet scored 72.7%; Claude Fable 5 scored 95%. Claude Fable 5 wins this benchmark.
Operational comparison
Runtime and commercial metrics are compared only when both models have a complete sourced value.
| Metric | Claude 4 Sonnet | Claude Fable 5 | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | Claude 4 Sonnet$3 input / $15 output | Claude Fable 5$10 input / $50 output | Claude 4 Sonnet has the lower combined listed price. |
| Generation speedtokens per second | Claude 4 Sonnet40 tok/s | Claude Fable 5Not available | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | Claude 4 Sonnet1.33 s | Claude Fable 5Not available | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | Claude 4 Sonnet200K | Claude Fable 51M+ | Claude Fable 5 lists the larger context window. |
Benchmark Deep Dive
Agentic15 benchmarks
| Benchmark | Claude 4 Sonnet | Claude Fable 5 | Result |
|---|---|---|---|
| τ²-bench resultsSource | 52.3% | 98.5% | Claude Fable 5 leads |
| Gert LabsSource | 39.66% | — | Not comparable |
| JobBenchSource | 18.4% | — | Not comparable |
| Terminal-Bench 2.0Source | — | 84.3% | Not comparable |
| OSWorld-VerifiedSource | — | 85% | Not comparable |
| GDPval-AASource | — | 1748 | Not comparable |
| AA Agentic IndexSource | — | 52.8% | Not comparable |
| GDPval-AASource | — | 62.4% | Not comparable |
| AA BriefcaseSource | — | 1574 | Not comparable |
| AA AutomationBenchSource | — | 48.6% | Not comparable |
| AA EnterpriseOps-GymSource | — | 51.1% | Not comparable |
| AA Harvey LABSource | — | 93.6% | Not comparable |
| AA Tau3 BankingSource | — | 26.8% | Not comparable |
| terminalBenchHardSource | — | 62.9% | Not comparable |
| aaTerminalBench21Source | — | 84.6% | Not comparable |
CodingClaude Fable 5 wins9 benchmarks
| Benchmark | Claude 4 Sonnet | Claude Fable 5 | Result |
|---|---|---|---|
| SWE-bench VerifiedSource | 72.7% | 95% | Claude Fable 5 leads |
| AA-SciCodeSource | 37.3% | 60.2% | Claude Fable 5 leads |
| SWE-bench ProSource | — | 80% | Not comparable |
| FrontierCode 1.1 MainSource | — | 53.5% | Not comparable |
| Terminal-Bench 2.0Source | — | 84.3% | Not comparable |
| cursorBench31Source | — | 70.6% | Not comparable |
| cursorBench32Source | — | 70.5% | Not comparable |
| VulcanBench v3Source | — | 87.0% | Not comparable |
| AA Coding IndexSource | — | 76.5% | Not comparable |
Reasoning2 benchmarks
Knowledge6 benchmarks
| Benchmark | Claude 4 Sonnet | Claude Fable 5 | Result |
|---|---|---|---|
| Artificial Analysis Intelligence IndexSource | 25.5% | 59.9% | Claude Fable 5 leads |
| AA-GPQA DiamondSource | 68.3% | 92.6% | Claude Fable 5 leads |
| AA-HLESource | 4.0% | 53.3% | Claude Fable 5 leads |
| AA-Omniscience IndexSource | -9.2% | 40.2% | Claude Fable 5 leads |
| AA-Omniscience AccuracySource | 22.4% | 61.4% | Claude Fable 5 leads |
| AA-Omniscience Hallucination RateSource | 40.8% | 54.9% | Claude 4 Sonnet leads |
Multimodal4 benchmarks
Inst. Following1 benchmarks
| Benchmark | Claude 4 Sonnet | Claude Fable 5 | Result |
|---|---|---|---|
| AA-IFBenchSource | 45.4% | 63.5% | Claude Fable 5 leads |
Frequently Asked Questions (2)
Which is better, Claude 4 Sonnet or Claude Fable 5?
Claude Fable 5 is ahead on BenchLM's BenchAlign leaderboard, 83.68 to 42.79. The biggest single separator in this matchup is SWE-bench Verified, where the scores are 72.7% and 95%.
Which is better for coding, Claude 4 Sonnet or Claude Fable 5?
Claude Fable 5 has the edge for coding in this comparison, averaging 89.2 versus 72.7. Inside this category, AA-SciCode is the benchmark that creates the most daylight between them.
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