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Claude Sonnet 4.5

Anthropic · Claude 4

Balanced Claude tier for production reasoning, coding, and long-context assistant workflows.

Part of Claude Sonnet family · Other versions: Claude Sonnet 4.6
Type
multimodal
Context
200K tokens
Max Output
64K tokens
Status
current
API Access
Yes
License
proprietary
reasoning coding multimodal tool-use balanced
Released October 2025 · Updated March 6, 2026

Overview

Freshness note: Model capabilities, limits, and pricing can change quickly. This profile is a point-in-time snapshot last verified on February 15, 2026.

Claude Sonnet 4.5 is Anthropic’s balanced production tier for teams that need reliable quality for coding, analysis, and writing without always paying Opus-level rates. Anthropic’s current docs still position Sonnet-class models as the default place to start for most real workloads.

Capabilities

The model is effective in structured reasoning, technical writing, implementation planning, and tool-enabled assistant workflows. It is a strong fit for mixed enterprise tasks where instruction fidelity and predictable behavior matter more than frontier benchmark chasing.

Technical Details

Anthropic’s current public model materials frame Sonnet as the broad production utility tier. In practice, that means coding, document analysis, support operations, and assistant flows where quality needs to be strong but cost still matters at scale.

Pricing & Access

Current Anthropic base pricing for Sonnet-class models is documented at 3per1Minputtokensand3 per 1M input tokens and 15 per 1M output tokens. Access is available through Anthropic API, AWS Bedrock, Google Vertex AI, and Claude product surfaces, but teams should still verify exact plan and alias availability before rollout.

Best Use Cases

Good choice for engineering copilots, technical documentation workflows, analysis-heavy support tooling, and mid-to-high complexity product planning.

Comparisons

Compared with Claude Opus 4.6, Sonnet 4.5 is more cost-efficient but less powerful on the hardest reasoning tasks. Compared with GPT-5.4, Sonnet is often chosen for Anthropic-native workflows and output style preferences. Compared with Gemini 2.5 Pro, selection depends on multimodal needs and platform strategy.