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AnthropicProprietary
Claude Sonnet 4.5
Claude Sonnet 4.5 is a foundation model developed by Anthropic. Designed for chat specialization, it supports an extremely extensive context window of 1000K.
Parameters
Undisclosed
Context Window
1000K
License
Proprietary
Release Date
2025-09-30
API Pricing
API pricing for this model is not yet available
Strengths
- ・Extremely long 1000K context understanding
- ・Advanced conversational chat capability
- ・Latest design by Anthropic
Weaknesses
- ・Non-open-source license
- ・Closed system with private internals
- ・Usage restrictions in closed environments
Use Cases
- ・Analyzing ultra-large documents
- ・Long-context conversational dialogues
- ・Building advanced AI chatbots
Deep Analysis
SWE-Bench Verified
77.2%
best at launch (Sept 2025)
GPQA Diamond
83.4%
strong reasoning
OSWorld
61.4%
SOTA computer use at launch
Input Price
$3/1M
same as Sonnet 4
Output Price
$15/1M
same as Sonnet 4
Context Window
200K tokens
1M beta at Tier 4+
Strengths
- ・Best coding model at launch (SWE-bench Verified 77.2%)
- ・Price parity with Sonnet 4 — pure capability upgrade
- ・Outstanding computer use (OSWorld 61.4%, 45% over Sonnet 4)
- ・Fast output speed (63 tok/s)
Weaknesses
- ・200K context window (1M in beta only)
- ・Superseded by Sonnet 4.6 and 4.8
- ・GPQA Diamond (83.4%) trails frontier models (94%+)
Competitor Comparison
| Model | Arena | SWE | GPQA | Price |
|---|---|---|---|---|
| Claude Sonnet 4.6 | ~1490 | 79.6% | 89.9% | $3/$15 |
| GPT-5.4 | 1467 | 80.8% | 94.4% | $2.50/$15 |
| Claude Sonnet 4.5 | ~1460 | 77.2% | 83.4% | $3/$15 |
Analysis generated: 2026-05-24