Context Window

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GPT-4o-mini Search Preview vs GPT-5.2-Codex

This page is context-first: how much text each model can take in one request. Full specs adds capabilities and limits; the pricing matrix below is only about $/million tokens from hosts that list both models.

Openai

Model

GPT-4o-mini Search Preview

Image inputTool calling

Context window

128K

128,000 tokens · ~96K words

Model page
Openai

Model

GPT-5.2-Codex

Image inputTool calling

Context window

272K

272,000 tokens · ~204K words

Model page

Context window · side by side

Bar length is relative to the larger of the two windows (100% = max of this pair). This is not pricing.

GPT-4o-mini Search Preview128K
GPT-5.2-Codex272K

GPT-5.2-Codex has about 2.1× the context window of the other in this pair.

Token calculator →Memory savings →

GPT-5.2-Codex has 112% more context capacity (272K vs 128K tokens). GPT-4o-mini Search Preview is 91% cheaper on input.

Quick verdicts

Short takeaways — validate with your own workloads.

  • Long document processing

    Use GPT-5.2-Codex. Its 272K context fits entire documents without chunking (vs 128K).

  • RAG / high-volume retrieval

    Use GPT-4o-mini Search Preview. Input tokens are 91% cheaper — critical when sending large retrieved contexts.

  • Long output (reports, code files)

    Use GPT-5.2-Codex. Its 128K max output lets you generate complete artifacts in one request.

Full specs

Context, output, capabilities, and dates. Green highlights the favorable value where we compute a winner.

SpecGPT-4o-mini Search PreviewGPT-5.2-Codex
Context window128,000 tokens (128K)272,000 tokens (272K)
Max output tokens16,384 tokens (16K)128,000 tokens (128K)
Speed tierFastBalanced
VisionYesYes
Function callingYesYes
Extended thinkingNoYes
Prompt cachingYesYes
Batch APIYesNo
Release dateMar 2025Jan 2026

Pricing matrix

Dollar rates only: hosts that list both models, per 1M tokens. For how much text fits, use the context section above — not this table.

ProviderGPT-4o-mini Search Preview inGPT-4o-mini Search Preview outGPT-5.2-Codex inGPT-5.2-Codex out
Openai$0.150/M$0.600/M——
Openrouter——$1.75/M$14.00/M

Frequently asked questions

GPT-5.2-Codex has a larger context window: 272K tokens vs 128K. For long documents, large codebases, or extended agent sessions, the larger context window reduces the need to chunk inputs or summarize history.

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Mem0 gives your AI long-term memory so you stop re-sending context on every call. That means you can use a smaller, faster, cheaper model — and still get better answers.

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Example: a multi-turn chat session

Without Mem0~128K tokens sent
Full history
Repeated info
Old context
With Mem0~20K tokens sent
Key memories
Current turn

80% less to send — works with any model