Question 1

How much does GPT-5.3 Codex cost?

Accepted Answer

GPT-5.3 Codex costs $1.75 per 1 million input tokens and $14 per 1 million output tokens. This pricing is set by OpenAI.

Question 2

What tokenizer does GPT-5.3 Codex use?

Accepted Answer

GPT-5.3 Codex uses the o200k_base tokenizer. This is OpenAI's latest tokenizer, optimized for efficiency with a vocabulary of ~200,000 tokens.

Question 3

What is GPT-5.3 Codex's context window?

Accepted Answer

GPT-5.3 Codex supports a context window of 400K tokens (400,000 tokens). The maximum output length is 33K tokens.

Question 4

How does GPT-5.3 Codex compare to other models?

Accepted Answer

You can compare GPT-5.3 Codex's pricing and capabilities against other LLMs in the comparison table above, or visit the full pricing page for a side-by-side view of all models.

Question 5

How do I count tokens for GPT-5.3 Codex?

Accepted Answer

Use the token counter at the top of this page or visit the homepage calculator. Paste your text and it will show the exact token count and cost for GPT-5.3 Codex using the o200k_base tokenizer.

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