GPT-4o (Omni)vsGrok 4
GPT-4o (Omni) is cheaper than Grok 4 at $2.5/M vs $3/M input tokens.
| Spec | GPT-4o (Omni) | Grok 4 |
|---|---|---|
| Input price | $2.5/M tokens | $3/M tokens |
| Output price | $10/M tokens | $15/M tokens |
| Context window | 128K tokens | 256K tokens |
| Parameters | Not disclosed | Not disclosed |
| Weights | Closed | — |
| Free API (OpenRouter) | No | No |
| Released | May 2024 | Jul 2025 |
| GPQA | 53.1% | 87-88% |
Our Verdict
GPT-4o (Omni)
Grok 4
Not enough votes to call it. On the specs, nothing separates them.
Too close to call
API pricing
Cost per 1M tokens
GPT-4o (Omni)
Input
$2.50
1.2× cheaper
Output
$10.00
1.5× cheaper
Grok 4
Input
$3.00
Output
$15.00
GPT-4o (Omni) is cheaper on both: 1.2× input, 1.5× output.
Where to run it
2 hosts
Grok 4
No hosts listed on OpenRouter.
Per million tokens. Prices and uptime via OpenRouter, checked 9 Sep 2026.
Writing DNA
Style Comparison
Similarity
39%
Grok 4 uses 23.8x more emoji
GPT-4o (Omni)
Grok 4
54%Vocabulary56%
18wSentence Length18w
0.72Hedging0.65
7.3Bold2.4
5.6Lists2.4
0.03Emoji0.60
1.40Headings0.73
0.26Transitions0.06
Based on 24 + 26 text responses
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