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Google Gemini vs OpenAI GPT: Complete Comparison 2026

Compare Google Gemini 3.1/2.5 models with OpenAI GPT-5.5/5.4 models. Pricing, context windows, and performance across different use cases.

Last updated: May 2026

Pricing Comparison

Model Provider Input $/1M Output $/1M Context Max Output
Gemini 3.1 Pro Google $2 $12 2M 16K
GPT-5.5 OpenAI $5 $30 1.05M 128K
Gemini 2.5 Flash Google $0.3 $2.5 1M 65K
GPT-5.4 OpenAI $2.5 $15 1.05M 128K

Detailed Comparison

Gemini 3.1 Pro

Google

$2 / $12

per 1M tokens

Strengths

  • + Largest context window (2M tokens)
  • + Lower input price than GPT-5.5
  • + Strong Google flagship reasoning model

Best For

Long document analysis, cost-effective premium tasks

Context Window

2M

Max Output

16K

GPT-5.5

OpenAI

$5 / $30

per 1M tokens

Strengths

  • + Broader ecosystem support
  • + More mature API and tooling
  • + Strong multi-modal capabilities

Best For

Enterprise applications, broad integration needs

Context Window

1.05M

Max Output

128K

Gemini 2.5 Flash

Google

$0.3 / $2.5

per 1M tokens

Strengths

  • + Extremely cost-effective
  • + 1M context at flash speed
  • + Great for high-volume processing

Best For

High-volume tasks, budget-conscious applications

Context Window

1M

Max Output

65K

GPT-5.4

OpenAI

$2.5 / $15

per 1M tokens

Strengths

  • + Large 1.05M context window
  • + Good balance of price and quality
  • + Reliable for production

Best For

Production workloads needing large context

Context Window

1.05M

Max Output

128K

Verdict

Gemini 3.1 Pro offers the largest canonical context window here (2M) at $2/$12, while GPT-5.5 is the premium OpenAI option at $5/$30. Gemini 2.5 Flash remains the lower-cost high-volume option at $0.30/$2.50. Choose Gemini for massive context and cost savings; choose GPT for ecosystem maturity and OpenAI integration fit.

Calculate Your Costs

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FAQ

Which is cheaper, Gemini 3.1 Pro or GPT-5.5?

Gemini 3.1 Pro costs $2/$12 per million tokens (input/output), while GPT-5.5 costs $5/$30. Gemini 3.1 Pro is cheaper for input.

Which has a larger context window?

Gemini 3.1 Pro supports 2M context, while GPT-5.5 supports 1.05M. Larger context windows allow processing more text in a single request.

Which should I choose for my project?

Gemini 3.1 Pro offers the largest canonical context window here (2M) at $2/$12, while GPT-5.5 is the premium OpenAI option at $5/$30. Gemini 2.5 Flash remains the lower-cost high-volume option at $0.30/$2.50. Choose Gemini for massive context and cost savings; choose GPT for ecosystem maturity and OpenAI integration fit.