Key Takeaways
GPT-5.3 Codex wins:
- No clear advantages in compared metrics
GPT-5 wins:
- Cheaper input tokens
- Cheaper output tokens
- Faster response time
- Higher intelligence benchmark
- Better at coding
- Better at math
- Supports tool calls
Price Advantage
GPT-5
Benchmark Advantage
GPT-5
Context Window
GPT-5
Speed
GPT-5
Pricing Comparison
Price Comparison
| Metric | GPT-5.3 Codex | GPT-5 | Winner |
|---|---|---|---|
| Input (per 1M tokens) | $1.75 | $1.25 | GPT-5 |
| Output (per 1M tokens) | $14.00 | $10.00 | GPT-5 |
| Cache Read (per 1M) | $0.17 | $0.13 | GPT-5 |
Using a 3:1 input/output ratio, GPT-5 is 29% cheaper overall.
GPT-5.3 Codex Providers
OpenAI $1.75 (Cheapest)
GPT-5 Providers
OpenAI $1.25 (Cheapest)
Azure $1.25 (Cheapest)
Benchmark Comparison
8
Benchmarks Compared
0
GPT-5.3 Codex Wins
0
GPT-5 Wins
Benchmark Scores
| Benchmark | GPT-5.3 Codex | GPT-5 | Winner |
|---|---|---|---|
Intelligence Index Overall intelligence score | - | 44.6 | - |
Coding Index Code generation & understanding | - | 36.0 | - |
Math Index Mathematical reasoning | - | 94.3 | - |
MMLU Pro Academic knowledge | - | 87.1 | - |
GPQA Graduate-level science | - | 85.4 | - |
LiveCodeBench Competitive programming | - | 84.6 | - |
Aider Real-world code editing | - | 88.0 | - |
AIME Competition math | - | 95.7 | - |
GPT-5 significantly outperforms in coding benchmarks.
Cost vs Quality
X-axis:
Y-axis:
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Other models
Context & Performance
Context Window
GPT-5.3 Codex
400,000
tokens
Max output: 128,000 tokens
GPT-5
400,000
tokens
Max output: 128,000 tokens
Speed Performance
| Metric | GPT-5.3 Codex | GPT-5 | Winner |
|---|---|---|---|
| Tokens/second | N/A | 94.0 tok/s | |
| Time to First Token | N/A | 102.36s |
Capabilities
Feature Comparison
| Feature | GPT-5.3 Codex | GPT-5 |
|---|---|---|
| Vision (Image Input) | ||
| Tool/Function Calls | ||
| Reasoning Mode | ||
| Audio Input | ||
| Audio Output | ||
| PDF Input | ||
| Prompt Caching | ||
| Web Search |
License & Release
| Property | GPT-5.3 Codex | GPT-5 |
|---|---|---|
| License | Proprietary | Proprietary |
| Author | OpenAI | OpenAI |
| Released | Feb 2026 | Aug 2025 |
GPT-5.3 Codex Modalities
Input
textimage
Output
text
GPT-5 Modalities
Input
textimagefile
Output
text