Claude Sonnet 4.5
ActiveBalanced performance and speed.
Updated 4 days agoStructured data from Modeldex catalog
VisionAgenticLong contextCode
Knowledge cutoff
Jan 31, 2025(1.2 years ago)
API release
Sep 29, 2025(7 months ago)
Not enough benchmark coverage yet for an Intelligence Index — needs at least 3 results across 2 categories.
History
Claude Sonnet 4.5 became available via the Anthropic API on 2025-09-29.
Training & availability
Training data has a knowledge cutoff of 2025-01-31 — information about events after that date is unlikely to appear in the model's responses. Anthropic has not released the underlying model weights — access is via their hosted API only.
Capabilities
-
Context window: 200K tokens.
-
Max output: 64K tokens.
-
Input modalities: text, image.
Recommended for: vision, agentic, long-context, code.
Limitations
- The knowledge cutoff is 14 months old — this model will not know about recent events, releases, or API changes.
Quick start
Minimal example using the anthropic API. Copy, paste, replace the key.
from anthropic import Anthropic
client = Anthropic(api_key="sk-ant-...")
resp = client.messages.create(
model="claude-sonnet-4-5",
max_tokens=1024,
messages=[{"role": "user", "content": "Explain quantum computing in one sentence."}],
)
print(resp.content[0].text)Benchmarks
| Benchmark | Score | Source |
|---|---|---|
| SWE-bench VerifiedCoding | 70.3% resolved | Third-party Papers With Code |
Integrations & tooling support
- Tool calling
- Supported
- Structured outputs
- Supported
Price vs quality
Competent benchmarks
Solid benchmark performance. Pricing not publicly available — check the provider.
- Quality percentile
- 72.2%
- Effective price
- —
- Pricing breakdown
- — in
— out
vs 1 benchmark
pricing not available
Community ratings
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Comments
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