OpenAI: GPT-5 Codex
Analysis Summary
GPT-5 Codex is an OpenAI coding model with measured strength in mathematical reasoning, software coding, tool interaction, and instruction following. Its 400K context window supports substantial repositories and long technical sessions, while vision enables workflows involving screenshots, diagrams, or visual debugging. Function calling and tool use make it suitable for agentic development environments.
The model fits complex software engineering, terminal-based task execution, code review, and client projects where error reduction matters more than token cost. Its agentic and coding profile is useful, but the lower general intelligence index and terminal score indicate that autonomous workflows still need checkpoints and test gates. Input pricing is manageable, while output pricing is premium, so route routine coding requests to a cheaper model and reserve this model for difficult tasks.
Assessed September 7, 2026
Editorial notes
GPT-5 Codex combines strong coding results, tool use, function calling, vision, and a 400K context window for software agents. Premium output pricing makes it better suited to high-value engineering work than bulk automation.
Rankings consider pricing, capabilities, benchmarks, and real-world applicability and are refreshed as new models launch. Feedback?
DFO Verdict
GPT-5 Codex combines strong coding results, tool use, function calling, vision, and a 400K context window for software agents. Premium output pricing makes it better suited to high-value engineering work than bulk automation.
Benchmark scores
Magenta = intelligence · Ink = technical/agentic · Cyan = content & long-context · Grey = community benchmarks. Data: Artificial Analysis, Hugging Face.
29.2 Intelligence Index·98.7 Math Index
How OpenAI: GPT-5 Codex compares
OpenAI: GPT-5 Codex ranks #95 of 435 AI models we track for overall intelligence. Its 400K-token context window is larger than 75% of the models we list. At $1.25 per million input tokens it is cheaper than 23% of comparable models.
Dark bar = input · light bar = output, scaled to the priciest peer.
1M tokens ≈ 8 full-length novels or ~2,500 pages of business documents in a single request.
Strongest on business fit. The pulled-in technical corner is the trade-off, and if the shape matters more than the price, this is your model.
Compare shapes side-by-side →Pricing
| Token Type | Cost per 1M tokens | Cost per 1K tokens |
|---|---|---|
| Input | $1.25 | $0.001250 |
| Output | $10.00 | $0.010000 |
What would OpenAI: GPT-5 Codex cost your business?
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A website chatbot handling around 100 customer conversations a day, a few short messages each.
Full calculator with 756 models → Price Calculator
These numbers get smaller with the right architecture.
We route routine calls to cheap models and save OpenAI: GPT-5 Codex for the hard ones. Most clients cut their estimate by 60-80%.
Talk to our teamAbout OpenAI: GPT-5 Codex
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..
Frequently asked questions about OpenAI: GPT-5 Codex
How much does OpenAI: GPT-5 Codex cost?
OpenAI: GPT-5 Codex costs $1.25 per million input tokens and $10.00 per million output tokens.
What is the context window of OpenAI: GPT-5 Codex?
OpenAI: GPT-5 Codex has a context window of 400,000 tokens (400K).
What can OpenAI: GPT-5 Codex do?
OpenAI: GPT-5 Codex supports image/vision input, tool use, and function calling.
Who created OpenAI: GPT-5 Codex?
OpenAI: GPT-5 Codex is developed by OpenAI and was released on September 23, 2025.