Key Takeaways
Gemini 1.5 Flash wins:
- Cheaper input tokens
- Cheaper output tokens
GPT-5.3 Codex wins:
- Larger context window
- Faster response time
- Higher intelligence benchmark
- Better at coding
- Supports vision
Price Advantage
Gemini 1.5 Flash
Benchmark Advantage
GPT-5.3 Codex
Context Window
GPT-5.3 Codex
Speed
GPT-5.3 Codex
Pricing Comparison
Price Comparison
| Metric | Gemini 1.5 Flash | GPT-5.3 Codex | Winner |
|---|---|---|---|
| Input (per 1M tokens) | $0.35 | $1.75 | Gemini 1.5 Flash |
| Output (per 1M tokens) | $1.05 | $14.00 | Gemini 1.5 Flash |
| Cache Read (per 1M) | N/A | $0.17 | GPT-5.3 Codex |
Using a 3:1 input/output ratio, Gemini 1.5 Flash is 89% cheaper overall.
Gemini 1.5 Flash Providers
No provider data available
GPT-5.3 Codex Providers
No provider data available
Benchmark Comparison
6
Benchmarks Compared
0
Gemini 1.5 Flash Wins
2
GPT-5.3 Codex Wins
Benchmark Scores
| Benchmark | Gemini 1.5 Flash | GPT-5.3 Codex | Winner |
|---|---|---|---|
Intelligence Index Overall intelligence score | 13.8 | 54.0 | |
Coding Index Code generation & understanding | - | 53.1 | - |
MMLU Pro Academic knowledge | 68.0 | - | - |
GPQA Graduate-level science | 46.3 | 91.5 | |
LiveCodeBench Competitive programming | 27.3 | - | - |
AIME Competition math | 18.0 | - | - |
GPT-5.3 Codex significantly outperforms in coding benchmarks.
Cost vs Quality
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Gemini 1.5 Flash
Other models
Context & Performance
Context Window
Gemini 1.5 Flash
N/A
tokens
GPT-5.3 Codex
400,000
tokens
Speed Performance
| Metric | Gemini 1.5 Flash | GPT-5.3 Codex | Winner |
|---|---|---|---|
| Tokens/second | 0.0 tok/s | 68.3 tok/s | |
| Time to First Token | 0.00s | 81.66s |
GPT-5.3 Codex responds Infinity% faster on average.
Capabilities
Feature Comparison
| Feature | Gemini 1.5 Flash | GPT-5.3 Codex |
|---|---|---|
| Vision (Image Input) | ||
| Tool/Function Calls | ||
| Reasoning Mode | ||
| Audio Input | ||
| Audio Output | ||
| PDF Input | ||
| Prompt Caching | ||
| Web Search |
License & Release
| Property | Gemini 1.5 Flash | GPT-5.3 Codex |
|---|---|---|
| License | Proprietary | Proprietary |
| Author | OpenAI | |
| Released | Unknown | Feb 2026 |
Gemini 1.5 Flash Modalities
Input
Output
GPT-5.3 Codex Modalities
Input
textimage
Output
text