by OpenAI

OpenAI: GPT-5.1.

multimodal closed 400K ctx
Cheapest input
$1.25/M
on OpenAI API
Cheapest output
$10.0/M
on OpenAI API
Fastest
79 tok/s
on OpenRouter
Hosted equiv.
~$3.6/hr
@ 100 tok/s on OpenAI API

GPT-5.1 is the latest frontier-grade model in the GPT-5 series, offering stronger general-purpose reasoning, improved instruction adherence, and a more natural conversational style compared to GPT-5. It uses adaptive rea

Hosted API only

No self-host path — closed weights.

OpenAI: GPT-5.1'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
OpenAI API api direct $1.25 $10.0 Launch ↗
OpenRouter api aggregator $1.25 $10.0 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 78.7 835 ms 1816 ms
FAQ

Frequently asked.

How do I run OpenAI: GPT-5.1?
OpenAI: GPT-5.1 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 OpenAI: GPT-5.1?
OpenAI: GPT-5.1 is available via OpenAI API, OpenRouter. Each access option lists its own pricing (per million tokens or hourly hosting).
How much does it cost to run OpenAI: GPT-5.1?
API pricing starts at $1.25/M input tokens and $10.0/M output tokens. Self-hosting cost depends on the GPU you rent — see the Run It Yourself tab.
Is OpenAI: GPT-5.1 open-source or proprietary?
OpenAI: GPT-5.1 is a proprietary model from OpenAI. Access is API-only — there are no public weights to download.