OpenAI: GPT-5 Codex

OpenAI: GPT-5 Codex

openai · Released Sep 23, 2025 Professional
Intelligence #29 / 525
79.1 Our Score
Speed #29 / 244
197.1 tokens / sec
Input #417 / 525
$1.25 per 1M tokens
Output #451 / 525
$10.00 per 1M tokens
Context #59 / 525
400,000 tokens

Analysis Summary

OpenAI: GPT-5 Codex sits in the Professional tier on our leaderboard, ranked #29 of 525 published models on overall intelligence. At $1.25 input and $10.00 output per 1M tokens, it is among the most expensive on the market. It offers a generous context window for extended reasoning and code review and supports tool use, function calling, vision, and reasoning.

Editorial notes

OpenAI's GPT-5 Codex is a highly capable model from an established provider, with excellent reasoning, coding, and agentic benchmark scores, vision support, and a 400K context window, making it a strong choice for complex business workflows despite its premium pricing.

Assessed April 23, 2026

Rankings consider pricing, capabilities, benchmarks, and real-world applicability and are refreshed as new models launch. Feedback?

Performance Profile

Intelligence7.9Technical7.7Value6.5Content8
Intelligence 7.9/10
Technical 7.7/10
Content 8/10
Value 6.5/10

GPT-5-Codex is a specialized version of GPT-5 optimized for software engineering and coding workflows. It is designed for both interactive development sessions and long, independent execution of complex engineering tasks..

Capabilities

Tool Use Function Calling Vision

Performance Indices

Source: Artificial Analysis

44.6 Intelligence Index
38.9 Coding Index
62.3 Agentic Index
98.7 Math Index

Benchmark Scores

Intelligence

GPQA Diamond 83.7% Graduate-level scientific reasoning
HLE 25.6% Humanity's Last Exam
MMLU Pro 86.5% Multi-task language understanding
AIME 2025 98.7% Competition mathematics (2025)
SciCode 40.9% Scientific computing

Technical

LiveCodeBench 84% Live coding evaluation
TerminalBench Hard 37.9% Agentic terminal tasks
τ²-Bench 86.8% Conversational agent benchmark

Content

IFBench 74.1% Instruction following
LCR 69% Long-context reasoning

Benchmark data from Artificial Analysis and Hugging Face

How does OpenAI: GPT-5 Codex stack up?

Compare side-by-side with other professional models.

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Model Information

OpenRouter ID openai/gpt-5-codex
Provideropenai
Release Date September 23, 2025
Context Length400,000 tokens
Max Completion128,000 tokens
Status Active

Pricing

Token Type Cost per 1M tokens Cost per 1K tokens
Input $1.25 $0.001250
Output $10.00 $0.010000

Live Performance

Live endpoint metrics — refreshed every 30 minutes.

100%
Avg Uptime
2,103ms
Best Latency (TTFT)
54 tok/s
Best Throughput
1/1
Active Endpoints
Available via: OpenAI

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