Skip to contentGPT-5.3
LegacyVerified ·
An earlier GPT-5 generation flagship, superseded by GPT-5.5; still available for workloads pinned to its behavior.
profile normalized against the 47-model field
Context window· 1.05M of 1.05M100%
Max output· 128K of 272K47%
Output speed· 95 tok/s30%
Affordability· $21.00 / Mtok out89%
Capability breadth· 7 of 1164%
Capability switches · 7 of 11
Reasoning mode
Tool / function use
Streaming
JSON mode
Structured outputs
Prompt caching
Fine-tuning
Web search
Code execution
Vision input
Audio input
Specifications
Every value carries a primary source and a verification date.
Pricing
Input $/Mtok$3.50 / Mtok USD/Mtok
Cached input $/Mtok$0.35 / Mtok USD/Mtok
Output $/Mtok$21.00 / Mtok USD/Mtok
Performance
Output speed95 tok/s tok/s
Time to first token520 ms ms
Capabilities
Input modalitiesText, image
Tool / function useYes
General
Knowledge cutoffSeptember 2025
Benchmarks
Sourced evaluation scores, each verified against its primary source.
GPQA Diamond
GPQA Diamond: 79.1%
SWE-bench Verified
SWE-bench Verified: 68.9%
AIME 2025
AIME 2025: 88.4%
LiveCodeBench
LiveCodeBench: 70.2%