Model comparison
Claude Sonnet 4.5 vs Claude Sonnet 4
- Input
- $3.00
- Output
- $15.00
- Context
- 1M
- Released
- 2025-09-29
- Input
- $3.00
- Output
- $15.00
- Context
- 200K
- Released
- 2025-05-22
Claude Sonnet 4.5 scores higher on 1 of the 1 benchmarks both models report; both charge the same $3 per 1M input tokens; Claude Sonnet 4.5 has the larger context window (1M vs 200K).
Specs and pricing side by side
| Spec | Claude Sonnet 4.5 | Claude Sonnet 4 |
|---|---|---|
| Maker | Anthropic | Anthropicsame |
| Released | 2025-09-29 | 2025-05-22 |
| Context window | 1M | 200K |
| Max output | 64K | 64Ksame |
| Input price | $3.00 | $3.00same |
| Output price | $15.00 | $15.00same |
| License | Proprietary | Proprietarysame |
| Weights | API only | API onlysame |
| Modalities | Text, Vision, PDF | Text, Vision, PDFsame |
| Knowledge cutoff | January 2025 | March 2025 |
Not published by either maker: parameters.
Benchmarks both models report
| Benchmark | Claude Sonnet 4.5 | Claude Sonnet 4 |
|---|---|---|
| SWE-bench Verified | 77.2% | 72.7% |
Scores are as published by each maker or its cited source; harness, reasoning effort and date can differ between rows, so treat small gaps as ties. Sources are listed on each model page.
Which one should you pick?
Pick Claude Sonnet 4.5 if…
- You care about SWE-bench Verified (it scores higher on 1 shared benchmark).
- You need the longer context (1M vs 200K).
- Your use case is: long-running autonomous coding agents and multi-hour build tasks.
Pick Claude Sonnet 4 if…
- Your use case is: agentic coding and software-engineering tasks.
FAQ
Which is better, Claude Sonnet 4.5 or Claude Sonnet 4?
Claude Sonnet 4.5 scores higher on 1 of the 1 benchmarks both models report; both charge the same $3 per 1M input tokens; Claude Sonnet 4.5 has the larger context window (1M vs 200K). The better pick depends on whether you value benchmark scores, price per token, context length or openness for your workload.
How do Claude Sonnet 4.5 and Claude Sonnet 4 pricing compare?
Claude Sonnet 4.5: $3.00 input, $15.00 output. Claude Sonnet 4: $3.00 input, $15.00 output (list API prices as published by each maker).
What are the context windows of Claude Sonnet 4.5 and Claude Sonnet 4?
Claude Sonnet 4.5 offers 1M with up to 64K output; Claude Sonnet 4 offers 200K with up to 64K output.
Is Claude Sonnet 4.5 newer than Claude Sonnet 4?
Claude Sonnet 4.5 was released 2025-09-29; Claude Sonnet 4 was released 2025-05-22.