OpenAI

GPT-5.1 is the newest top-tier model in the GPT-5 series, featuring enhanced general reasoning, better instruction following, and a more natural conversational tone compared to GPT-5. With adaptive reasoning, it dynamically adjusts its computational effort—responding swiftly to simple queries and diving deeper into complex tasks. Explanations are now clearer and use less jargon, making challenging topics easier to grasp. Designed for a wide range of tasks, GPT-5.1 consistently improves performance in math, coding, and structured analysis, offering more cohesive long-form responses and more reliable tool usage. Its conversation style is warmer and more intuitive, yet still precise. GPT-5.1 stands as the main, fully capable successor to GPT-5.

Pricing

Pay-as-you-go rates for this model. More details can be found here.

Input Tokens (1M)

$0.63

Cached Input Tokens (1M)

$0.06

Output Tokens (1M)

$5.00

Capabilities

Input Modalities

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Output Modalities

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Supported Parameters

Available parameters for API requests

Frequency PenaltyFunction CallFunctionsLogit BiasMax Completion TokensParallel Tool CallsPredictionPresence PenaltyReasoning EffortResponse FormatStopTool ChoiceToolsWeb Search Options

GPT 5.1

Input Tokens (1M)

Cached Input Tokens (1M)

Output Tokens (1M)

Input Modalities

Output Modalities