Claude Sonnet 4.5 is deprecated: it is still functional but no longer recommended, and retires on November 30, 2026. Recommended replacement: Claude Sonnet 5.5.
See Claude Sonnet 5.5Models & pricingLegacy models
Claude Sonnet 4.5Deprecated
- 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 5.5 | 1M | 128K | $4 / $20 | Adaptive (always on) | medium | Jun 2026 |
| Claude Sonnet 5.5 | 1M | 128K | $2 / $10 | Adaptive | high | Jun 2026 |
| Claude Sonnet 4.5This model | 200K | 64K | $3 / $15 | Extended | — | Jan 2025 |
| Claude Haiku 5.5 | 1M | 128K | From $0.10 / $0.50 | Adaptive | medium | Jun 2026 |
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
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
- Deprecated
- Released
- September 29, 2025
- Deprecated
- September 30, 2026
- Retires
- November 30, 2026
Resources
What changes when moving from Claude Sonnet 4.5 and earlier Sonnet models to Claude Sonnet 5.5.
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.
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