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Grok 4 vs GPT-5.3 Codex
A detailed comparison of Grok 4 (xAI) and GPT-5.3 Codex (OpenAI) across pricing, performance, and features.
Pricing Comparison
| Metric | Grok 4 | GPT-5.3 Codex | Difference |
|---|---|---|---|
| Input / 1M tokens | $3.00 | $2.00 | -33% |
| Output / 1M tokens | $15.00 | $16.00 | +7% |
| Context window | 128K | 200K | — |
| Max output | 16.384K | 65.536K | — |
Benchmark Comparison
| Benchmark | Grok 4 | GPT-5.3 Codex |
|---|---|---|
| MMLU-Pro | 86% | 90% |
| HumanEval | 93% | 96.5% |
| GPQA | 72% | 78% |
Capabilities
| Capability | Grok 4 | GPT-5.3 Codex |
|---|---|---|
| code | ✓ | ✓ |
| reasoning | ✓ | ✓ |
| text | ✓ | ✓ |
| tool-use | ✓ | ✓ |
| vision | ✓ | ✓ |
| web-search | ✓ | ✗ |
Grok 4 Strengths
- ✓Built-in web search and real-time data
- ✓Strong reasoning
- ✓$25 free credits for new users
Grok 4 Weaknesses
- ✗Premium pricing for its benchmark tier
- ✗Additional charges for tool invocations ($2.50-$5/1K calls)
- ✗Smaller ecosystem than OpenAI/Anthropic
GPT-5.3 Codex Strengths
- ✓Best coding model from OpenAI
- ✓Large output window (65K tokens)
- ✓Strong reasoning for complex tasks
GPT-5.3 Codex Weaknesses
- ✗API access not yet available
- ✗Premium pricing
Quick Verdict
Best value: GPT-5.3 Codex is the more affordable option at $2/$16 per 1M tokens.
Higher benchmarks: GPT-5.3 Codex scores higher on average across available benchmarks (88.2% avg).
Larger context: GPT-5.3 Codex supports 200K tokens.
Choose GPT-5.3 Codex if cost matters most. Choose Grok 4 if you need the best possible quality for complex tasks.