Model Comparison

Gemini 3 Flash vs GPT-5.3 Codex

GPT-5.3 Codex significantly outperforms across most benchmarks. Gemini 3 Flash is 4.3x cheaper per token.

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Performance Benchmarks

Comparative analysis across standard metrics

1 benchmarks

Gemini 3 Flash outperforms in 0 benchmarks, while GPT-5.3 Codex is better at 1 benchmark (Terminal-Bench 2.0).

GPT-5.3 Codex significantly outperforms across most benchmarks.

Tue Apr 07 2026 • llm-stats.com

Arena Performance

Human preference votes

Pricing Analysis

Price comparison per million tokens

Gemini 3 Flash costs less

For input processing, Gemini 3 Flash ($0.50/1M tokens) is 3.5x cheaper than GPT-5.3 Codex ($1.75/1M tokens).

For output processing, Gemini 3 Flash ($3.00/1M tokens) is 4.7x cheaper than GPT-5.3 Codex ($14.00/1M tokens).

In conclusion, GPT-5.3 Codex is more expensive than Gemini 3 Flash.*

* Using a 3:1 ratio of input to output tokens

Lowest available price from all providers
Tue Apr 07 2026 • llm-stats.com
Google
Gemini 3 Flash
Input tokens$0.50
Output tokens$3.00
Best providerGoogle
OpenAI
GPT-5.3 Codex
Input tokens$1.75
Output tokens$14.00
Best providerOpenAI
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Context Window

Maximum input and output token capacity

Gemini 3 Flash accepts 1,000,000 input tokens compared to GPT-5.3 Codex's 400,000 tokens. GPT-5.3 Codex can generate longer responses up to 128,000 tokens, while Gemini 3 Flash is limited to 65,536 tokens.

Google
Gemini 3 Flash
Input1,000,000 tokens
Output65,536 tokens
OpenAI
GPT-5.3 Codex
Input400,000 tokens
Output128,000 tokens
Tue Apr 07 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Both Gemini 3 Flash and GPT-5.3 Codex support multimodal inputs.

They are both capable of processing various types of data, offering versatility in application.

Gemini 3 Flash

Text
Images
Audio
Video

GPT-5.3 Codex

Text
Images
Audio
Video

License

Usage and distribution terms

Both models are licensed under proprietary licenses.

Both models have usage restrictions defined by their respective organizations.

Gemini 3 Flash

Proprietary

Closed source

GPT-5.3 Codex

Proprietary

Closed source

Release Timeline

When each model was launched

Gemini 3 Flash was released on 2025-12-17, while GPT-5.3 Codex was released on 2026-02-05.

GPT-5.3 Codex is 2 months newer than Gemini 3 Flash.

Gemini 3 Flash

Dec 17, 2025

3 months ago

GPT-5.3 Codex

Feb 5, 2026

2 months ago

1mo newer

Knowledge Cutoff

When training data ends

Gemini 3 Flash has a documented knowledge cutoff of 2025-01-31, while GPT-5.3 Codex's cutoff date is not specified.

We can confirm Gemini 3 Flash's training data extends to 2025-01-31, but cannot make a direct comparison without GPT-5.3 Codex's cutoff date.

Gemini 3 Flash

Jan 2025

GPT-5.3 Codex

—

Provider Availability

Gemini 3 Flash is available from Google. GPT-5.3 Codex is available from OpenAI.

Gemini 3 Flash

google logo
Google
Input Price:Input: $0.50/1MOutput Price:Output: $3.00/1M

GPT-5.3 Codex

openai logo
OpenAI
Input Price:Input: $1.75/1MOutput Price:Output: $14.00/1M
* Prices shown are per million tokens

Outputs Comparison

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Key Takeaways

Google
Larger context window (1,000,000 tokens)
Less expensive input tokens
Less expensive output tokens
OpenAI
Higher Terminal-Bench 2.0 score (77.3% vs 47.6%)

Detailed Comparison

AI Model Comparison Table
Feature
Google
Gemini 3 Flash
OpenAI
GPT-5.3 Codex

FAQ

Common questions about Gemini 3 Flash vs GPT-5.3 Codex

GPT-5.3 Codex significantly outperforms across most benchmarks. Gemini 3 Flash is made by Google and GPT-5.3 Codex is made by OpenAI. The best choice depends on your use case — compare their benchmark scores, pricing, and capabilities above.
Gemini 3 Flash scores Vending-Bench 2: 100.0%, AIME 2025: 99.7%, Global PIQA: 92.8%, MMMLU: 91.8%, GPQA: 90.4%. GPT-5.3 Codex scores SWE-Lancer (IC-Diamond subset): 81.4%, Cybersecurity CTFs: 77.6%, Terminal-Bench 2.0: 77.3%, OSWorld-Verified: 64.7%, SWE-Bench Pro: 56.8%.
Gemini 3 Flash is 3.5x cheaper for input tokens. Gemini 3 Flash costs $0.50/M input and $3.00/M output via google. GPT-5.3 Codex costs $1.75/M input and $14.00/M output via openai.
Gemini 3 Flash supports 1.0M tokens and GPT-5.3 Codex supports 400K tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.
Key differences include context window (1.0M vs 400K), input pricing ($0.50 vs $1.75/M). See the full comparison above for benchmark-by-benchmark results.
Gemini 3 Flash is developed by Google and GPT-5.3 Codex is developed by OpenAI.