Key Takeaways
GPT-5.3 Codex wins:
- Cheaper input tokens
- Cheaper output tokens
- Larger context window
- Faster response time
- Higher intelligence benchmark
- Better at coding
Grok 4 wins:
- Better at math
Price Advantage
GPT-5.3 Codex
Benchmark Advantage
GPT-5.3 Codex
Context Window
GPT-5.3 Codex
Speed
GPT-5.3 Codex
Pricing Comparison
Price Comparison
| Metric | GPT-5.3 Codex | Grok 4 | Winner |
|---|---|---|---|
| Input (per 1M tokens) | $1.75 | $3.00 | GPT-5.3 Codex |
| Output (per 1M tokens) | $14.00 | $15.00 | GPT-5.3 Codex |
| Cache Read (per 1M) | $0.17 | $0.75 | GPT-5.3 Codex |
Using a 3:1 input/output ratio, GPT-5.3 Codex is 20% cheaper overall.
GPT-5.3 Codex Providers
No provider data available
Grok 4 Providers
No provider data available
Benchmark Comparison
8
Benchmarks Compared
3
GPT-5.3 Codex Wins
0
Grok 4 Wins
Benchmark Scores
| Benchmark | GPT-5.3 Codex | Grok 4 | Winner |
|---|---|---|---|
Intelligence Index Overall intelligence score | 54.0 | 41.5 | |
Coding Index Code generation & understanding | 53.1 | 40.5 | |
Math Index Mathematical reasoning | - | 92.7 | - |
MMLU Pro Academic knowledge | - | 86.6 | - |
GPQA Graduate-level science | 91.5 | 87.7 | |
LiveCodeBench Competitive programming | - | 81.9 | - |
Aider Real-world code editing | - | 79.6 | - |
AIME Competition math | - | 94.3 | - |
GPT-5.3 Codex 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
Grok 4
256,000
tokens
GPT-5.3 Codex has a 36% larger context window.
Speed Performance
| Metric | GPT-5.3 Codex | Grok 4 | Winner |
|---|---|---|---|
| Tokens/second | 68.4 tok/s | 48.1 tok/s | |
| Time to First Token | 87.36s | 10.29s |
GPT-5.3 Codex responds 42% faster on average.
Capabilities
Feature Comparison
| Feature | GPT-5.3 Codex | Grok 4 |
|---|---|---|
| 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 | Grok 4 |
|---|---|---|
| License | Proprietary | Proprietary |
| Author | OpenAI | Xai |
| Released | Feb 2026 | Jul 2025 |
GPT-5.3 Codex Modalities
Input
textimage
Output
text
Grok 4 Modalities
Input
imagetext
Output
text