Claude 4.5 Sonnet (Reasoning)
Claude 4.5 Sonnet (Reasoning) is an API model from Anthropic. It’s positioned for general text tasks—work that benefits from iteration, not just one-shot answers.
Intelligence
Good
Speed
Slow
50 tok/s output
Cost
High
$3.75 in / $15.00 out
Context
1M
Up to 1,000,000 tokens
How are Intelligence, Speed & Cost bucketed?
Intelligence and Speed buckets are percentile ranks on
Artificial Analysis. Cost buckets are fixed dollar
thresholds keyed off output-token price ($/M out).
Intelligence
- Top 1%≤ 1%
- Top 5%≤ 5%
- Top 10%≤ 10%
- Good≤ 25%
- Medium≤ 50%
- Below avg> 50%
Speed
- Top 1%≥ 345 tok/s
- Top 5%≥ 237 tok/s
- Top 10%≥ 196 tok/s
- Good≥ 146 tok/s
- Medium≥ 90 tok/s
- Slow< 90 tok/s
Cost
- Freeopen weights · self-host
- Low< $1 / M out
- Moderate$1–5 / M out
- High≥ $5 / M out
Core Capabilities
Long Documents
Handles entire codebases, books, and multi-doc RAG.
Context Window
1M tokens
≈ entire codebase
4k Chat 聊天
32k Long docs 长文档
128k Books 整本书
400k Multi-doc 多文档
1M This model 本模型
10M
Availability
API
Available
Product / App
Not available
Open Source
Not released
Enterprise
Contact sales
Pricing Model
Pay per token
Input and output billed separately.
Pay-per-token Capability / Performance
Where this model sits relative to the middle 60% of models in the tree. All scores are 0–10 (higher is better).
Lower 20% Upper 80% This model
Context / memory
Context window size · log-scaled
6.0
9.0
9.0
Lower 20% 20th percentile — 20% of models score below this This model Where the current model lands Upper 80% 80th percentile — only 20% of models score above this
Percentile boundaries are computed across every model in the tree that reports the underlying benchmark for each capability.
What it feels like
- 77.2% on SWE-bench Verified at release — highest-scoring Claude model in standard runs (82.0% with parallel compute)
- Sustains 30+ hour autonomous coding tasks — Anthropic's headline reliability claim
- 61.4% on OSWorld for computer use, 100% AIME 2025 with Python tools, 83.4% GPQA Diamond
Best use cases
- Production agentic coding (Devin, Cursor, Cline, Claude Code) where reliability matters
- Long-running autonomous tasks (>30h) without losing the thread
- Cost-sensitive teams that want frontier coding without Opus pricing
Tools to try
Not ideal for
- Hardest reasoning tasks — Opus 4.5/4.6 lead by ~7 points on AA Intelligence Index
- Workloads needing 1M-token context (Sonnet 4.5 ships 200K)
Model Evolution
Claude is Anthropic's language model family.