Gemini 3.1 Pro vs GPT-5.3 Codex
Compare Google and OpenAI AI models
Cost Comparison (1000 input + 500 output tokens, 100 requests/day)
Gemini 3.1 Pro
GPT-5.3 Codex
Cost Differences
GPT-5.3 Codex costs more than Gemini 3.1 Pro
Feature Comparison
| Feature | Gemini 3.1 Pro | GPT-5.3 Codex |
|---|---|---|
| Provider | OpenAI | |
| Input Price | $2.00/1M tokens | $1.75/1M tokens |
| Output Price | $12.00/1M tokens | $14.00/1M tokens |
| Context Window | 1,000,000 tokens | 256,000 tokens |
| Max Output | 65,536 tokens | 32,768 tokens |
| Category | flagship | coding |
| Capabilities | textvisionaudiovideocodereasoning | textcode |
| Release Date | 2/19/2026 | 3/1/2026 |
Gemini 3.1 Pro vs GPT-5.3 Codex: Which Should You Choose?
Choosing between Gemini 3.1 Pro and GPT-5.3 Codex depends on your priorities: cost efficiency, context length, or raw capability. Gemini 3.1 Pro is the more affordable option at $2.00/1M input tokens. Meanwhile, Gemini 3.1 Pro offers a significantly larger context window at 1,000,000 tokens vs 256,000 for GPT-5.3 Codex.
These models come from different providers — Google and OpenAI — which means different API ecosystems, SDKs, rate limits, and terms of service. If you're already integrated with Google, switching to OpenAIinvolves migration effort beyond just pricing. Factor in your existing infrastructure when deciding.
These models target different tiers: Gemini 3.1 Pro is a flagship model while GPT-5.3 Codex is coding. This means they're optimized for different workloads. Gemini 3.1 Pro is built for complex tasks that require deeper reasoning, while GPT-5.3 Codex offers better value for routine operations.
Output costs matter too. Gemini 3.1 Pro charges $12.00/1M output tokens vs $14.00 for GPT-5.3 Codex. For generation-heavy workloads (content creation, code generation, summarization), output pricing often dominates your bill. Gemini 3.1 Pro has the edge here at $12.00/1M output tokens.
Multimodal capabilities: Gemini 3.1 Pro supports vision (image inputs) while GPT-5.3 Codex is text-only. If your application needs image understanding, this narrows your choice.
Best Use Cases
Choose Gemini 3.1 Pro when:
- • You need a larger context window (1,000,000 tokens)
- • You need more capabilities (vision, audio, video, reasoning)
- • You need longer outputs (up to 65,536 tokens)
- • You're already using Google's API ecosystem
Choose GPT-5.3 Codex when:
- • Budget is a primary concern
- • You're already using OpenAI's API ecosystem
Try Different Scenarios
Use the calculator below to see how costs change with different usage patterns
Gemini 3.1 Pro (Google)
GPT-5.3 Codex (OpenAI)
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