GPT-5.3 Chat
MultimodalGPT-5.3 Chat is the instant model used in ChatGPT, released on March 4, 2026. It pairs high intelligence with medium speed, supports text and image inputs with a 128k context window, and offers streaming, function calling, and structured outputs at $1.75/1M input and $14.00/1M output tokens.
Key Specifications
Parameters
-
Context
128.0K
Release Date
March 4, 2026
Average Score
40.0%
Timeline
Key dates in the model's history
Announcement
March 4, 2026
Today
August 27, 2026
Technical Specifications
Parameters
-
Training Tokens
-
Knowledge Cutoff
August 31, 2025
Family
-
Capabilities
MultimodalZeroEval
Pricing & Availability
Input (per 1M tokens)
$1.75
Output (per 1M tokens)
$14.00
Max Input Tokens
128.0K
Max Output Tokens
16.4K
Supported Features
Function CallingStructured OutputCode ExecutionWeb SearchBatch InferenceFine-tuning
Benchmark Results
Model performance metrics across various tests and benchmarks
Other Tests
Specialized benchmarks
HealthBench
HealthBench overall score. Down from 55.4% (GPT-5.2 Instant). • Self-reported
HealthBench Hard
HealthBench Hard subset. Down from 26.8% (GPT-5.2 Instant). • Self-reported
License & Metadata
License
proprietary
Announcement Date
March 4, 2026
Last Updated
August 27, 2026
Similar Models
All ModelsGPT-5.1 Codex Mini
OpenAI
MM
Released:Nov 2025
Price:$0.25/1M tokens
GPT-4.1 nano
OpenAI
MM
Best score:0.8 (MMLU)
Released:Apr 2025
Price:$0.10/1M tokens
GPT-5.4 Pro
OpenAI
MM
Released:Mar 2026
Price:$15.00/1M tokens
o3-pro
OpenAI
MM
Released:Jun 2025
Price:$20.00/1M tokens
GPT-5.1 Medium
OpenAI
MM
Released:Nov 2025
Price:$1.00/1M tokens
GPT-5.1 Codex High
OpenAI
MM
Released:Nov 2025
Price:$1.25/1M tokens
GPT-5.3 Codex
OpenAI
MM
Released:Feb 2026
Price:$1.75/1M tokens
GPT-5.1 Codex
OpenAI
MM
Released:Nov 2025
Price:$1.25/1M tokens
Recommendations are based on similarity of characteristics: developer organization, multimodality, parameter size, and benchmark performance. Choose a model to compare or go to the full catalog to browse all available AI models.