Model comparison

Gemini 3.5 Flash vs GPT-5.1 Codex Max

Compare Gemini 3.5 Flash (Google) and GPT-5.1 Codex Max (OpenAI) by price, context, capabilities, and latency.

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Price deadline

Gemini Flash prices rise Jan 1, 2027

Per Google's published pricing page, Gemini Flash input prices double on Jan 1, 2027. The same workload runs an order of magnitude cheaper on DeepSeek and GLM. Source: Google pricing Full price breakdown

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Which should you pick?

  • Price: Gemini 3.5 Flash is cheaper ($1.50 / 1M tokens input / $9 / 1M tokens output) vs GPT-5.1 Codex Max ($1.25 / 1M tokens input / $10 / 1M tokens output).
  • Context: Gemini 3.5 Flash has the larger context window (1M tokens).

Side by side

Gemini 3.5 Flash vs GPT-5.1 Codex Max — full comparison

Compare price, provider, context, capabilities, latency, and source basis.

ModelProviderInputOutputContextCapabilitiesBest forLatencyStatusSource
Gemini 3.5 Flashgoogle/gemini-3.5-flashGoogle$1.50 / 1M tokens$9 / 1M tokens1M
StreamingTool callingJSON modeVision
image understanding, multimodal chat0-0msCatalogPlatform curated
GPT-5.1 Codex Maxopenai/gpt-5.1-codex-maxOpenAI$1.25 / 1M tokens$10 / 1M tokens400k
StreamingTool callingJSON modeVision
image understanding, multimodal chat1802-3024msCatalogPlatform curated

FAQ

Gemini 3.5 Flash vs GPT-5.1 Codex Max FAQ

Is Gemini 3.5 Flash or GPT-5.1 Codex Max cheaper?

Gemini 3.5 Flash is cheaper ($1.50 / 1M tokens input / $9 / 1M tokens output) vs GPT-5.1 Codex Max ($1.25 / 1M tokens input / $10 / 1M tokens output). Actual cost depends on your input/output token mix — estimate it with the pricing calculator.

Which has a larger context window, Gemini 3.5 Flash or GPT-5.1 Codex Max?

Gemini 3.5 Flash is larger (1M tokens) vs 400k tokens.

Gemini 3.5 Flash vs GPT-5.1 Codex Max for Vision: which should I pick?

Both target Vision. Pick Gemini 3.5 Flash to optimize cost, or Gemini 3.5 Flash for the longer context window. Test both on real prompts before committing production traffic.

Gemini 3.5 Flash detailsGPT-5.1 Codex Max detailsPricing calculatorOpenAI-compatible quickstart