Model comparison
Claude 4 Sonnet vs Claude Sonnet 4.5
Head-to-head evidence from 4 shared benchmark results across 3 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.
Public leaderboard positions: Claude 4 Sonnet #158 (Supported); Claude Sonnet 4.5 #96 (Estimated). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. Claude 4 Sonnet and Claude Sonnet 4.5 share 4 comparable benchmark results. 1 of 8 categories are comparable. 12 results are unique to Claude 4 Sonnet; 8 to Claude Sonnet 4.5.
Updated July 22, 2026- Shared results
- 4
- Claude 4 Sonnet only
- 12
- Claude Sonnet 4.5 only
- 8
- Comparable categories
- 1 / 8
Pick Claude Sonnet 4.5 if you want the stronger benchmark profile. Claude 4 Sonnet only becomes the better choice if its workflow or ecosystem matters more than the raw scoreboard.
Confidence note. This is a partial-evidence comparison with 4 shared benchmark results across 3 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 Sonnet 4.5 is clearly ahead on the BenchAlign aggregate, 53.61 to 42.79. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
Claude Sonnet 4.5's sharpest advantage is in coding, where it averages 77.2 against 72.7. The single biggest benchmark swing on the page is SWE-bench Verified, 72.7% to 77.2%.
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 Sonnet 4.5 |
|---|---|---|---|
| Coding | Claude 4 Sonnet72.7 | Margin→ 4.5 | Claude Sonnet 4.577.2 |
| Agentic | Claude 4 SonnetNot measured | MarginNo overlap | Claude Sonnet 4.555.4 |
| Reasoning | Claude 4 SonnetNot measured | MarginNo overlap | Claude Sonnet 4.513.6 |
| Knowledge | Claude 4 SonnetNot measured | MarginNo overlap | Claude Sonnet 4.583.4 |
| Math | Claude 4 SonnetNot measured | MarginNo overlap | Claude Sonnet 4.511.2 |
Decisive benchmark drivers
The largest measured benchmark gaps in this matchup, with exact reported values.
More
- Source ↗
SWE-bench Verified
CodingA 72.7%B 77.2%Winner: Claude Sonnet 4.5Δ 4.5SWE-bench Verified: Claude 4 Sonnet scored 72.7%; Claude Sonnet 4.5 scored 77.2%. Claude Sonnet 4.5 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 Sonnet 4.5 | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | Claude 4 Sonnet$3 input / $15 output | Claude Sonnet 4.5$3 input / $15 output | Listed prices are equal. |
| Generation speedtokens per second | Claude 4 Sonnet40 tok/s | Claude Sonnet 4.5Not available | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | Claude 4 Sonnet1.33 s | Claude Sonnet 4.5Not available | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | Claude 4 Sonnet200K | Claude Sonnet 4.5200K | Listed context windows are equal. |
Benchmark Deep Dive
Agentic6 benchmarks
| Benchmark | Claude 4 Sonnet | Claude Sonnet 4.5 | Result |
|---|---|---|---|
| τ²-bench resultsSource | 52.3% | — | Not comparable |
| Gert LabsSource | 39.66% | 48.51% | Claude Sonnet 4.5 leads |
| JobBenchSource | 18.4% | 27.7% | Claude Sonnet 4.5 leads |
| Terminal-Bench 2.0Source | — | 50% | Not comparable |
| OSWorld-VerifiedSource | — | 61.4% | Not comparable |
| VITA-BenchSource | — | 17.0% | Not comparable |
CodingClaude Sonnet 4.5 wins2 benchmarks
Reasoning3 benchmarks
Knowledge7 benchmarks
| Benchmark | Claude 4 Sonnet | Claude Sonnet 4.5 | Result |
|---|---|---|---|
| Artificial Analysis Intelligence IndexSource | 25.5% | — | Not comparable |
| AA-GPQA DiamondSource | 68.3% | — | Not comparable |
| AA-HLESource | 4.0% | — | Not comparable |
| AA-Omniscience IndexSource | -9.2% | — | Not comparable |
| AA-Omniscience AccuracySource | 22.4% | — | Not comparable |
| AA-Omniscience Hallucination RateSource | 40.8% | — | Not comparable |
| GPQASource | — | 83.4% | Not comparable |
Math3 benchmarks
Multimodal2 benchmarks
Inst. Following1 benchmarks
| Benchmark | Claude 4 Sonnet | Claude Sonnet 4.5 | Result |
|---|---|---|---|
| AA-IFBenchSource | 45.4% | — | Not comparable |
Frequently Asked Questions (2)
Which is better, Claude 4 Sonnet or Claude Sonnet 4.5?
Claude Sonnet 4.5 is ahead on BenchLM's BenchAlign leaderboard, 53.61 to 42.79. The biggest single separator in this matchup is SWE-bench Verified, where the scores are 72.7% and 77.2%.
Which is better for coding, Claude 4 Sonnet or Claude Sonnet 4.5?
Claude Sonnet 4.5 has the edge for coding in this comparison, averaging 77.2 versus 72.7. Inside this category, SWE-bench Verified is the benchmark that creates the most daylight between them.
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