Gemini 3 Flash vs GPT-5.3 Codex
Gemini 3 Flash and GPT-5.3 Codex are closely matched at 36.8 and 36.5 on the LLM Stats Score. Gemini 3 Flash is 4.3x cheaper per token.
Google · OpenAI · Updated for 2026
Which is better?
Gemini 3 Flash and GPT-5.3 Codex are closely matched on the overall LLM Stats Score at 36.8 and 36.5.
In the 2 individual benchmarks reported for both models, GPT-5.3 Codex wins 2; this is a narrower head-to-head signal than the composite indexes.
On price, Gemini 3 Flash is roughly 4.3x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
Gemini 3 Flash also accepts a larger context window (1,000,000 input tokens), making it the stronger choice for long documents and large codebases.
Based on current LLM Stats indexes, shared benchmarks, pricing, and model metadata for 2026.
Choose Gemini 3 Flash
- cost matters — it's about 4.3x cheaper per token
- you process long inputs — it offers a 1,000,000 token context window
Choose GPT-5.3 Codex
- you value its reported benchmark strengths — it wins 2 of 2 exact shared results
- you want the most recent training data — it shipped Feb 2026
At a glance
The differences that matter most.
Individual benchmarks
24 reported for Gemini 3 Flash · 6 for GPT-5.3 Codex
Gemini 3 Flash outperforms in 0 benchmarks, while GPT-5.3 Codex is better at 2 benchmarks (LiveBench, Terminal-Bench 2.0).
GPT-5.3 Codex significantly outperforms across most benchmarks.
Human preference
Blind head-to-head votes and playground preference scores
Pricing Analysis
Price comparison per million tokens
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
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.
Input capabilities
Documented input modalities across available providers
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
GPT-5.3 Codex
License
Usage and distribution terms
Both models are licensed under proprietary licenses.
Both models have usage restrictions defined by their respective organizations.
Proprietary
Closed source
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.
Dec 17, 2025
9 months ago
Feb 5, 2026
7 months ago
1mo newerKnowledge 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.
Jan 2025
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Provider Availability
Gemini 3 Flash is available from Google. GPT-5.3 Codex is available from OpenAI.
Gemini 3 Flash
GPT-5.3 Codex
Outputs Comparison
Judge for yourself.
Run your own prompts against Gemini 3 Flash and GPT-5.3 Codex side-by-side, then vote on the output you prefer.
FAQ
Common questions about Gemini 3 Flash vs GPT-5.3 Codex.