Data points: 87
The readout for Claude Sonnet 4 and Claude Sonnet 4.5, before the detailed comparison sheet.
Decision read
Claude Sonnet 4.5
Claude Sonnet 4.5 currently has the stronger profile, with verified wins split 0 to 6.
Evidence depth
87 data points
Includes 8 benchmark rows, 1 audit samples, and 9 provider examples.
Selection signal
Start with Claude Sonnet 4.5
The charts below split 18 high-signal samples across speed, scores, and audit health.
Model compare Claude Sonnet 4 vs Claude Sonnet 4.5claude-sonnet-4-vs-claude-sonnet-4-5 | Model A Claude Sonnet 4 | Model B Claude Sonnet 4.5 |
|---|---|---|
| Overall leader | Contender | Leading |
| Verified metric wins | 0 wins | 6 wins |
| Where it leads | No data | Cheapest input price, Average speed, First-token latency, Free providers, Provider coverage, Recent tests |
Third-party benchmark profile synced into LMSpeed; only metrics available for both models are shown.
| Metric | Claude Sonnet 4 | Claude Sonnet 4.5 |
|---|---|---|
| MMLU-Pro | 83.7%#23 |
Latest completed audits from shared providers, with four safety and integrity score groups plus report links.
| Provider | Claude Sonnet 4 | Claude Sonnet 4.5 |
|---|---|---|
Winner: Claude Sonnet 4.5 | Claude Sonnet 4 claude-sonnet-4 No audit yet | Claude Sonnet 4.5 claude-sonnet-4.5 |
Speed aggregates and input/output pricing share each provider row for real API selection and migration cost checks.
| Provider | Claude Sonnet 4 | Claude Sonnet 4.5 |
|---|---|---|
15 tests | Claude Sonnet 4 speed / latency 36 tok/s / 6227ms input / output No data |
This report only uses LMSpeed data for Claude Sonnet 4 and Claude Sonnet 4.5: pricing, speed aggregates, third-party benchmark scores, and shared provider samples.
| Guidance | Claude Sonnet 4 | Claude Sonnet 4.5 |
|---|---|---|
| When to choose each model | Claude Sonnet 4 Claude Sonnet 4 does not clearly lead on the verified metrics here, so check provider-specific pricing before choosing. | Claude Sonnet 4.5 Claude Sonnet 4.5 is stronger when you prioritize Cheapest input price, Average speed, First-token latency, Free providers, Provider coverage, Recent tests. |
TL;DR: Claude Sonnet 4.5 leads across 87 verifiable data points, including pricing, speed, latency, benchmarks, and provider examples.
Continue from Claude Sonnet 4 vs Claude Sonnet 4.5 into nearby model comparisons with enough verified LMSpeed data.
| Model metadata | Claude Sonnet 4 exposes 1M tokens; notable signals: Text input, Image input, File input, Text output. | Claude Sonnet 4.5 exposes 1M tokens; notable signals: Text input, Image input, File input, Text output. |
|---|---|---|
| Developer | Anthropic | Anthropic |
| Context window | 1M tokens | 1M tokens |
| Max output | 64K tokens | 64K tokens |
| Released | May 2025 | Sep 2025 |
| Modalities | Input ImageTextFile Output Text | Input TextImageFile Output Text |
| Features | Text inputImage inputFile inputText outputTool callingReasoning | Text inputImage inputFile inputText outputTool callingStructured outputsJSON modeReasoning |
| Parameters | No data | No data |
| Tokenizer | Claude | Claude |
| Knowledge cutoff | 2025-01-31 | 2025-01-31 |
| OpenRouter ID | anthropic/claude-sonnet-4 | anthropic/claude-sonnet-4.5 |
| References | No data | No data |
| Time to first answer token | 1.07 s#24 | 1.55 s#37 |
|---|
| SciCode | 37.3%#64 | 42.8%#32 |
|---|
| Input price | $3.00/M#39 | $3.00/M#39 |
|---|
| Time to first token | 1.07 s#39 | 1.55 s#60 |
|---|
| LiveCodeBench | 44.9%#61 | 59.0%#44 |
|---|
| Output price | $15.00/M#44 | $15.00/M#44 |
|---|
| Blended price | $6.00/M#65 | $6.00/M#65 |
|---|
Audit score
91
Claude Sonnet 4.5
speed / latency
N/A / N/A
input / output
No data
Completions10 tests | Claude Sonnet 4 speed / latency 27 tok/s / 1036ms input / output No data | Claude Sonnet 4.5 speed / latency 21 tok/s / 1085ms input / output No data |
|---|
YUNWU API10 tests | Claude Sonnet 4 speed / latency N/A / N/A input / output No data | Claude Sonnet 4.5 speed / latency 41 tok/s / 3271ms input / output No data |
|---|
天宫造物10 tests | Claude Sonnet 4 speed / latency N/A / N/A input / output No data | Claude Sonnet 4.5 speed / latency 45 tok/s / 3170ms input / output No data |
|---|
CodeXE5 tests | Claude Sonnet 4 speed / latency N/A / N/A input / output No data | Claude Sonnet 4.5 speed / latency 44 tok/s / 2522ms input / output No data |
|---|
Claude Sonnet 4 claude-sonnet-4 speed / latency No data input / output $3.00/M / $15.00/M | Claude Sonnet 4.5 claude-sonnet-4.5 speed / latency No data input / output $0/M / $0/M |
Claude Sonnet 4 claude-sonnet-4 speed / latency No data input / output $0.020/M / $0.020/M | Claude Sonnet 4.5 claude-sonnet-4-5 speed / latency No data input / output $0.020/M / $0.020/M |
Claude Sonnet 4 claude-4-sonnet speed / latency No data input / output $1.03/M / $1.03/M | Claude Sonnet 4.5 claude-sonnet-4-5-20250929 speed / latency No data input / output $0.041/M / $0.205/M |
Claude Sonnet 4 claude-sonnet-4 speed / latency No data input / output $0.104/M / $0.521/M | Claude Sonnet 4.5 claude-sonnet-4-5-20250929 speed / latency No data input / output $0.104/M / $0.521/M |
Rankings are based on community-submitted tests and periodic health probes. Advisory only, not official data.
