by Anthropic

Anthropic: Claude Sonnet 4.5.

multimodal closed 1M ctx
Cheapest input
$3.0/M
on Anthropic API
Cheapest output
$15.0/M
on Anthropic API
Fastest
33 tok/s
on OpenRouter
Hosted equiv.
~$5.4/hr
@ 100 tok/s on Anthropic API

Claude Sonnet 4.5 is Anthropic’s most advanced Sonnet model to date, optimized for real-world agents and coding workflows. It delivers state-of-the-art performance on coding benchmarks such as SWE-bench Verified, with...

Hosted API only

No self-host path — closed weights.

Anthropic: Claude Sonnet 4.5's weights aren't published. Use it via the access providers below.

Where to use it

Cheapest hosted endpoints.

Provider Access $/M in $/M out
Anthropic API api direct $3.0 $15.0 Launch ↗
OpenRouter api aggregator $3.0 $15.0 Launch ↗
Performance

Speed across providers.

Tokens/sec and time-to-first-token measured against the same prompt template on each provider's API.

Provider Tokens/sec TTFT Total
OpenRouter 33.0 1621 ms 4395 ms
FAQ

Frequently asked.

How do I run Anthropic: Claude Sonnet 4.5?
Anthropic: Claude Sonnet 4.5 is a closed-source API model. The cheapest way to access it is through the API providers listed on this page (direct API, aggregators, and hosted chat UIs).
Where can I access Anthropic: Claude Sonnet 4.5?
Anthropic: Claude Sonnet 4.5 is available via Anthropic API, OpenRouter. Each access option lists its own pricing (per million tokens or hourly hosting).
How much does it cost to run Anthropic: Claude Sonnet 4.5?
API pricing starts at $3.0/M input tokens and $15.0/M output tokens. Self-hosting cost depends on the GPU you rent — see the Run It Yourself tab.
Is Anthropic: Claude Sonnet 4.5 open-source or proprietary?
Anthropic: Claude Sonnet 4.5 is a proprietary model from Anthropic. Access is API-only — there are no public weights to download.