Context Window

Compare

Claude Opus 4 8 Default vs Gemini Omni Flash Preview

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.

Anthropic

Model

Claude Opus 4 8 Default

Image inputTool calling

Context window

1M

1,000,000 tokens · ~750K words

Model page
Google

Model

Gemini Omni Flash Preview

Image input

Context window

1.0M

1,048,576 tokens · ~786K 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.

Claude Opus 4 8 Default1M
Gemini Omni Flash Preview1.0M

Gemini Omni Flash Preview has about 1× the context window of the other in this pair.

Token calculator →Memory savings →

Gemini Omni Flash Preview has 4% more context capacity (1048K vs 1000K tokens). Gemini Omni Flash Preview is 70% cheaper on input.

Quick verdicts

Short takeaways — validate with your own workloads.

  • Long document processing

    Use Gemini Omni Flash Preview. Its 1048K context fits entire documents without chunking (vs 1000K).

  • RAG / high-volume retrieval

    Use Gemini Omni Flash Preview. Input tokens are 70% cheaper — critical when sending large retrieved contexts.

  • Long output (reports, code files)

    Use Claude Opus 4 8 Default. 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.

SpecClaude Opus 4 8 DefaultGemini Omni Flash Preview
Context window1,000,000 tokens (1000K)1,048,576 tokens (1048K)
Max output tokens128,000 tokens (128K)65,535 tokens (65K)
Speed tierDeepFast
VisionYesYes
Function callingYesNo
Extended thinkingYesYes
Prompt cachingYesNo
Batch APIYesNo
Release dateN/AN/A

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.

ProviderClaude Opus 4 8 Default inClaude Opus 4 8 Default outGemini Omni Flash Preview inGemini Omni Flash Preview out
Google——$1.50/M$9.00/M
Google Vertex$5.00/M$25.00/M$1.50/M$9.00/M

Frequently asked questions

Gemini Omni Flash Preview has a larger context window: 1048K tokens vs 1000K. 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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Example: a multi-turn chat session

Without Mem0~128K tokens sent
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Repeated info
Old context
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