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Gemini 3.1 Pro vs GPT 5.3 Codex

At a glance
GoogleGemini 3.1 Pro

Google's frontier model with a large leap in core reasoning.

861.0M ctx$2.00/$12.00 per M#10/92
OpenAIGPT 5.3 Codex

OpenAI's most advanced agentic coding model with 400K context.

87400K ctx$1.75/$14.00 per M#8/92
AI Output
All AI outputs

No captured outputs for these models yet.

Benchmarks
See rankings
GoogleGemini 3.1 Pro
Reasoning
Sources:Epoch ECI·Epoch AI·Provider·OpenRouter· as of 2026-07-10
Cheaper
Capability
CapabilityECI86.4
Reasoning & Knowledge
Graduate Science94.1%Expert-Level46.4%Factual Recall77.3%
Math
Competition Math95.6%Research Math36.9%
Coding
Real-World Coding80.6%
Agentic
Terminal Tasks80.2%Novel Reasoning77.1%Task Horizon6.4h
OpenAIGPT 5.3 Codex
Reasoning
ReasoningInsufficient data
MathInsufficient data
Sources:Epoch ECI·Epoch AI·OpenRouter· as of 2026-07-10
Smarter
Capability
CapabilityECI87.0
Reasoning & Knowledge
Graduate Science—Expert-Level—Factual Recall—
Math
Competition Math—Research Math—
Coding
Real-World Coding74.8%
Agentic
Terminal Tasks78.4%Novel Reasoning—Task Horizon5.8h
Specs
GoogleGemini 3.1 Pro
1.0M
Context
66K
Max output
Feb 2026
Released
OpenAIGPT 5.3 Codex
400K
Context
128K
Max output
Feb 2026
Released
Capabilities
GoogleGemini 3.1 Pro
Vision
Audio
Reasoning
OpenAIGPT 5.3 Codex
Vision
Audio
Reasoning
Pricing
GoogleGemini 3.1 Pro
Live pricing, shown before you run
Input$2.00/M tokens
Output$12.00/M tokens
Reasoning$12.00/M tokens
Cache read$0.20/M tokens
Cache write$0.38/M tokens
Image input$2.00/M tokens
Audio input$2.00/M tokens
Web search$0.01/search
OpenAIGPT 5.3 Codex
Live pricing, shown before you run
Input$1.75/M tokens
Output$14.00/M tokens
Cache read$0.17/M tokens
Web search$0.01/search
Chat with Gemini 3.1 ProGo to model
Chat with GPT 5.3 CodexGo to model
Frequently Asked Questions: Gemini 3.1 Pro vs GPT 5.3 Codex▼

Which is better, Gemini 3.1 Pro or GPT 5.3 Codex?

▼

Based on the Capability Index, GPT 5.3 Codex scores higher (87.0 vs 86.4). However, "better" depends on your use case — pricing, speed, context window, and specific capability needs all matter.

Which is cheaper, Gemini 3.1 Pro or GPT 5.3 Codex?

▼

Gemini 3.1 Pro has a lower blended cost. Gemini 3.1 Pro: $2.00 input / $12.00 output. GPT 5.3 Codex: $1.75 input / $14.00 output.

Which has a larger context window, Gemini 3.1 Pro or GPT 5.3 Codex?

▼

Gemini 3.1 Pro has a larger context window: Gemini 3.1 Pro supports 1M tokens vs GPT 5.3 Codex at 400K tokens.

Do both Gemini 3.1 Pro and GPT 5.3 Codex support vision?

▼

Yes, both Gemini 3.1 Pro and GPT 5.3 Codex support vision/image input.

Which has better coding performance, Gemini 3.1 Pro or GPT 5.3 Codex?

▼

Gemini 3.1 Pro scores higher on SWE-bench Verified: Gemini 3.1 Pro resolves 81% vs GPT 5.3 Codex at 75%.

What are the key differences between Gemini 3.1 Pro and GPT 5.3 Codex?

▼

Gemini 3.1 Pro and GPT 5.3 Codex 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 3.1 Pro and GPT 5.3 Codex for free on idapt.app to see which performs better for your specific needs.

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