Claude Sonnet 4.5 Model Specs, Costs & Benchmarks (July 2026)
Claude Sonnet 4.5, developed by Anthropic, features a context window of 1M tokens. The model costs $3.00 per million tokens for input and $15.00 per million tokens for output. It was released on September 29, 2025, and has achieved impressive scores in various benchmarks.
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Overview
 Claude Sonnet 4.5 | |
|---|---|
Model Provider The organization behind this AI's development | Anthropic |
Input Context Window Maximum input tokens this model can process at once | 1M tokens |
Output Token Limit Maximum output tokens this model can generate at once | 64K tokens |
Release Date When this model first became publicly available | September 29, 2025 10 months ago September 29th, 2025 |
Knowledge Cutoff Latest training-data date reported by the provider | January 31, 2025 |
Pricing
| Claude Sonnet 4.5 | |
|---|---|
Short Context Pricing Base rates before a long-context threshold applies | |
Input Token Cost Cost per million input tokens | $3.00 per million tokens |
Output Token Cost Cost per million output tokens | $15.00 per million tokens |
Web Search Cost Additional cost for each web search operation | $0.01 per search |
Cache Read Cost Cost to reuse cached input tokens | $0.30 per million tokens |
Cache Write Cost Cost to write input tokens to the cache | $3.75 per million tokens |
1-Hour Cache Write Cost Cost to cache input tokens for one hour | $6.00 per million tokens |
Long Context Pricing Rates for prompts with 200,000 or more tokens | |
Input Token Cost Long-context input cost per million tokens | $6.00 per million tokens |
Output Token Cost Long-context output cost per million tokens | $22.50 per million tokens |
Cache Read Cost Long-context cache read cost per million tokens | $0.60 per million tokens |
Cache Write Cost Long-context cache write cost per million tokens | $7.50 per million tokens |
Capabilities & Features
| Claude Sonnet 4.5 | |
|---|---|
Input Types Supported input formats | textimagefile |
Output Types Supported output formats | text |
Tokenizer Text encoding system | Claude |
Key Features Advanced capabilities | ✓ Function Calling✓ Structured Output✓ Reasoning Mode✓ Content Moderation |
Reasoning Controls Defaults and configurable reasoning effort | Optional |
Benchmarks
| Claude Sonnet 4.5 | |
|---|---|
Intelligence Index Overall model quality across independent evaluations | 36.4 (Artificial Analysis index; higher is better) |
Coding Index Programming performance across independent evaluations | 52.1 (Artificial Analysis index; higher is better) |
Agentic Index Ability to complete multi-step agentic tasks | 24.6 (Artificial Analysis index; higher is better) |
Best Design Arena Score Highest human-preference Elo score across design arenas | 1,243 Elo (#11 in Asciiart (56.3% win rate)) |
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