Product
GPT-5.3-Codex: specs, API pricing and data
Updated
OpenAIAI Models & LLMs
- Context window
- 400k tokens
- Maximum output
- 128k tokens
- Input cost per 1M tokens
- $1.75
- Output cost per 1M tokens
- $14.00
- Knowledge cutoff
- August 2025
Data sheet · GPT-5.3-Codex
Every figure is quoted from the vendor's official page, with the date we read it. If a row is missing, the source does not state it and we do not estimate it.
Memory and answer length
- Context window
- 400k tokensRank 18 of 21
What it means and the source
How much text the model keeps in view in a single request, question and answer included. It matters for long documents and whole code projects. A token is a fragment of a word.
developers.openai.comOpens the source in a new tab Oct 23, 2026- Maximum output
- 128k tokensRank 3 of 16
What it means and the source
The longest answer it can write in one go: useful for reports, long code or translations of whole documents.
developers.openai.comOpens the source in a new tab Oct 23, 2026
API prices
- Input cost per 1M tokens
- $1.75Rank 10 of 21
What it means and the source
What it costs to have the model read a million tokens (your question, the documents, the code). It is the official list price, before discounts.
developers.openai.comOpens the source in a new tab Oct 23, 2026- Cached input cost per 1M tokens
- $0.175Rank 11 of 20
What it means and the source
The reduced price when part of the request is identical to one sent recently, for example the same instructions or the same document: the vendor keeps it in memory and charges less for it.
developers.openai.comOpens the source in a new tab Oct 23, 2026- Output cost per 1M tokens
- $14.00Rank 14 of 21
What it means and the source
What a million tokens written by the model cost. It usually costs more than the input and is the figure to watch when answers are long.
developers.openai.comOpens the source in a new tab Oct 23, 2026
Knowledge and abilities
- Knowledge cutoff
- August 2025Rank 9 of 9
What it means and the source
The month up to which the model's knowledge reaches. For more recent facts it needs web search or your documents.
developers.openai.comOpens the source in a new tab Oct 23, 2026- Reads images
- Yes13 models out of 23
What it means and the source
The model can take images (photos, screenshots, charts) as well as text.
developers.openai.comOpens the source in a new tab Oct 23, 2026
Questions and answers
GPT-5.3-Codex: how much does it cost through the API?
The official list price is $1.75 per 1M input tokens and $14.00 per 1M output tokens.
GPT-5.3-Codex: how much text can it read at once?
The context window is 400k tokens. It can write answers of up to 128k tokens.
GPT-5.3-Codex: how recent is its knowledge?
Its knowledge reaches August 2025. For more recent facts it needs web search or your documents.
The short version
On OpenAI GPT-5.3-Codex the figure that actually matters is Context window: 400,000. I took that figure from OpenAI – GPT-5.3-Codex. Among the 21 I checked, 17 do better. The other figure to look at is Output cost per 1M tokens: 14.
The numbers on OpenAI GPT-5.3-Codex
I put them in order of importance, with the value and the standing against the others I checked.
Context window: 400,000. Rank 18 of the 21 I compared.
Output cost per 1M tokens: 14. Rank 14 of the 21 I compared.
Input cost per 1M tokens: 1.75. Rank 10 of the 21 I compared.
Cached input cost per 1M tokens (USD): 0.175. Rank 10 of the 20 I compared.
Knowledge cutoff: Aug 31, 2025. Rank 9 of the 9 I compared.
Maximum output (k tokens): 128,000. Rank 3 of the 16 I compared.
Who it is for
Take it if Reads images is your priority: 1, and none of the ones I checked does better.
Look elsewhere if what matters to you is Context window: here it is 400,000, and 17 products do better.
Explore related coverage
Sources
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Reviews and tests
OpenAI GPT-5.3-Codex
Reviews and tests · OpenAI GPT-5.3-Codex
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What changed
- Page updated
- Page updated