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GPT-5.3-Codex

by OpenAI · Released Feb 2026

Multimodal
80.3
avg score
Rank #23
Compare
Better than 90% of all models
Context
400K tokens (~200 books)
Input $/1M
$1.75
Output $/1M
$14.00
Type
multimodal
License
Proprietary
Benchmarks
9 tested
Data updated today
About

GPT-5.3-Codex is OpenAI’s most advanced agentic coding model, combining the frontier software engineering performance of GPT-5.2-Codex with the broader reasoning and professional knowledge capabilities of GPT-5.2. It achieves state-of-the-art results...

Tested on 9 benchmarks with 52.2% average. Top scores: WeirdML (79.3%), Terminal Bench (77.3%), SWE-Bench verified (74.8%).

Looking for similar performance at lower cost?
MiMo-V2-Flash scores 81.7 (102% as good) at $0.09/1M input · 95% cheaper
Capabilities
coding
77.1
#8 globally
knowledge
17.8
#202 globally
agentic
32.1
#15 globally
speed
94.0
#3 globally
Benchmark Scores
Compare All
Tested on 9 benchmarks · Ranked across 4 categories
Score Distribution (all 233 models)
0255075100
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WeirdML

Unusual and adversarial machine learning challenges. Tests robustness of reasoning about edge cases in ML systems.

79.3
Terminal Bench

Complex terminal-based engineering tasks. Models must use command-line tools, navigate filesystems, and debug systems through shell interaction.

77.3
SWE-Bench verified

Real-world software engineering tasks from GitHub issues. Models must diagnose bugs and write patches that pass test suites. Human-verified subset of SWE-bench.

74.8
PostTrainBench

Evaluates post-training behaviors including instruction following, safety, and helpfulness balance.

17.8
SWE Atlas — Codebase QnA

SEAL SWE Atlas Codebase Q&A. Tests understanding of large codebases through question answering.

32.6
APEX-Agents

Agent performance evaluation testing multi-step tool use, planning, and execution in realistic environments.

31.7
Excellent (85+) Good (70-85) Average (50-70) Below (<50)
Links
Documentation
Community
BenchGecko API
gpt-5-3-codex
Specifications
  • Typemultimodal
  • Context400K tokens (~200 books)
  • ReleasedFeb 2026
  • LicenseProprietary
  • StatusActive
  • Cost / Message~$0.018
Available On
OpenAI logoOpenAI$1.75
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GPT-5.3-Codex is a proprietary multimodal AI model by OpenAI, released in February 2026. It has an average benchmark score of 80.3. Context window: 400K tokens.