// model_detail
legacy balanced
Claude Sonnet 4.5
by Anthropic
Previous-generation balanced model with extended thinking. 200K context.
Context window 200K 200K tokens
Max output 64K 64K tokens
Pricing /1M tok $3.00 in / $15.00 out per 1M tokens (API)
Released Sep 29, 2025
// specifications
Specs & capabilities
API details
- API model ID
claude-sonnet-4-5-20250929- Internal ID
claude-sonnet-4-5- Status
- legacy
- Type
- balanced
Capabilities
- Vision
- 👁️ Yes
- Function calling
- 🔧 Yes
- Knowledge cutoff
- 📅 2025-01
Pricing
- Input
- $3.00 / 1M tokens
- Output
- $15.00 / 1M tokens
- Source
- First-party API pricing
Lifecycle
- Predecessor
- Claude Sonnet 4
- Successor
- Claude Sonnet 4.6
// notes
Additional notes
Previous-gen balanced, superseded by 4.6
// more_from_anthropic
More Anthropic models
Claude Opus 4.6 active frontier
Anthropic's flagship model for complex agents and coding. Extended + adaptive thinking, 1M context, 128K output.
Claude Sonnet 4.6 active balanced
Fast balanced model with extended + adaptive thinking. 1M context, 64K output.
Claude Opus 4.5 legacy frontier
Previous-generation flagship. Extended thinking, 200K context.
Claude Haiku 4.5 active fast
Fastest Claude model with near-frontier intelligence. Extended thinking, 200K context, 64K output.
Claude Opus 4.1 legacy frontier
Premium reasoning model with extended thinking. 200K context, 32K output.
Claude Opus 4 legacy frontier
First-generation Claude 4 flagship. Extended thinking, 200K context, 32K output.
// external_links