Although Claude Sonnet 4.5 is still available, you should consider migrating to Claude Sonnet 5 for improved performance.
See Claude Sonnet 5Models & pricingLegacy models
Claude Sonnet 4.5Legacy
- Context window
- 200Ktokens
- Max output
- 64Ktokens
- Input pricing
- $3/ MTok
- Output pricing
- $15/ MTok
How it compares to the current lineup
| Model | Context | Max output | Price / MTok | Thinking | Default effort | Knowledge cutoff |
|---|---|---|---|---|---|---|
| Claude Fable 5.1 | 1M | 128K | $10 / $50 | Adaptive (always on) | high | Jun 2026 |
| Claude Opus 5 | 1M | 128K | $5 / $25 | Adaptive | high | May 2026 |
| Claude Sonnet 5 | 1M | 128K | $2 / $10 | Adaptive | high | Jan 2026 |
| Claude Sonnet 4.5This modelLegacy | 200K | 64K | $3 / $15 | Extended | — | Jan 2025 |
| Claude Haiku 4.5 | 200K | 64K | $1 / $5 | Extended | — | Feb 2025 |
Specifications
Model IDs
- Claude API
- Claude API alias
Pricing
- Input
- $3 / MTok
- Output
- $15 / MTok
- 5m cache write
- $3.75 / MTok
- 1h cache write
- $6 / MTok
- Cache read
- $0.30 / MTok
- Batch API
- 50% discount on input and output
- Full price list
- Pricing
Capabilities
- Context window
- 200K tokens
- Max output
- 64K tokens
- Thinking
- Extended
- Default effort
- Not supported
- Input → output
- Text and images → text
- Reliable knowledge cutoff
- Jan 2025
- Training data cutoff
- Jul 2025
Availability
- Status
- Active (legacy)
- Released
- September 29, 2025
- Retirement
- Not sooner than September 29, 2026
Resources
What changes when moving from Claude Sonnet 4.5 and earlier Sonnet models to Claude Sonnet 5.
The current Sonnet model: overview, specs, and resources.
Reference
The system prompt Claude Sonnet 4.5 uses on claude.ai and the Claude apps.
Safety evaluations and deployment decisions for Claude Sonnet 4.5.
Full price list, including batch discounts and prompt caching rates.
How model IDs, aliases, and pinned snapshots work.
Lifecycle status and retirement commitments for every Claude model.
Claude Sonnet 4.5 uses the InvokeModel Bedrock integration and Bedrock-style model IDs.
Was this page helpful?