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Gemini 3.8 Flash vs GPT 5.1 Codex Max

At a glance

Google's most intelligent Flash model, with significant gains over 3.7 Flash across software engineering, agentic tasks, and multi-step reasoning.

1.0M ctx$0.83/$4.13 per M

Extended-context coding model for large codebase operations.

400K ctx$1.25/$10.00 per M
Demos
All demos

No shared demos for these models yet.

AI Output
All AI outputs

No captured outputs for these models yet.

Benchmarks
See rankings
Reasoning
CodingInsufficient data
AgenticInsufficient data
Sources:Epoch AI·OpenRouter· as of 2026-10-02
Cheaper52%
Reasoning & Knowledge
Graduate Science95.4%Factual Recall69.7%
Math
Competition Math98.9%
Agentic
Terminal Tasks—Task Horizon—
Reasoning
CodingInsufficient data
ReasoningInsufficient data
MathInsufficient data
Sources:Epoch AI·OpenRouter· as of 2026-10-02
Reasoning & Knowledge
Graduate Science—Factual Recall—
Math
Competition Math—
Agentic
Terminal Tasks60.4%Task Horizon3.7h
Specs
1.0M
Context
66K
Max output
Sep 2026
Released
400K
Context
128K
Max output
Dec 2025
Released
Capabilities
Vision
Audio
Reasoning
Vision
Audio
Reasoning
Pricing
Live pricing, shown before you run
Input34%$0.83/M tokens
Output59%$4.13/M tokens
Reasoning$4.13/M tokens
Cache read34%$0.08/M tokens
Cache write$0.04/M tokens
Image input$0.83/M tokens
Audio input$0.83/M tokens
Web search$0.01/search
Live pricing, shown before you run
Input$1.25/M tokens
Output$10.00/M tokens
Cache read$0.13/M tokens
Web search29%$0.01/search
Chat with Gemini 3.8 FlashGo to model
Chat with GPT 5.1 Codex MaxGo to model
Frequently Asked Questions: Gemini 3.8 Flash vs GPT 5.1 Codex Max▼

Which is better, Gemini 3.8 Flash or GPT 5.1 Codex Max?

▼

Both Gemini 3.8 Flash and GPT 5.1 Codex Max are capable AI models. The best choice depends on your specific use case: consider pricing, context window, speed, and which capabilities (vision, reasoning, audio) you need.

Which is cheaper, Gemini 3.8 Flash or GPT 5.1 Codex Max?

▼

Gemini 3.8 Flash has a lower blended cost. Gemini 3.8 Flash: $0.83 input / $4.13 output. GPT 5.1 Codex Max: $1.25 input / $10.00 output.

Which has a larger context window, Gemini 3.8 Flash or GPT 5.1 Codex Max?

▼

Gemini 3.8 Flash has a larger context window: Gemini 3.8 Flash supports 1M tokens vs GPT 5.1 Codex Max at 400K tokens.

Do both Gemini 3.8 Flash and GPT 5.1 Codex Max support vision?

▼

Yes, both Gemini 3.8 Flash and GPT 5.1 Codex Max support vision/image input.

What are the key differences between Gemini 3.8 Flash and GPT 5.1 Codex Max?

▼

Gemini 3.8 Flash and GPT 5.1 Codex Max have similar overall capabilities. The main differences lie in pricing, context window size, and provider-specific strengths. Use this comparison page to review all metrics side by side.

Which model should I choose for my use case?

▼

If cost is your priority, choose the cheaper option. If you need the highest intelligence for complex tasks, pick the higher-scoring model. For long documents or codebases, choose the larger context window. You can try both Gemini 3.8 Flash and GPT 5.1 Codex Max for free on idapt.app to see which performs better for your specific needs.

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