GPT-4o minivsGPT-5.1-Codex
GPT-4o mini is cheaper than GPT-5.1-Codex at $0.15/M vs $1.25/M input tokens.
| Spec | GPT-4o mini | GPT-5.1-Codex |
|---|---|---|
| Input price | $0.15/M tokens | $1.25/M tokens |
| Output price | $0.6/M tokens | $10/M tokens |
| Context window | 128K tokens | 400K tokens |
| Weights | Closed | Closed |
| Free API (OpenRouter) | No | No |
| Released | Jul 2024 | Nov 2025 |
Our Verdict
GPT-5.1-Codex
GPT-4o miniRunner-up
Not enough votes to call it. On the specs, GPT-5.1-Codex has the edge: bigger model tier, newer, bigger context window.
GPT-4o mini costs 17x less per token.
Slight edge
Reviewing agent-written code?See a Brief PR report
API pricing
Cost per 1M tokens
GPT-4o mini
Input
$0.15
8.3× cheaper
Output
$0.60
17× cheaper
GPT-5.1-Codex
Input
$1.25
Output
$10.00
GPT-4o mini is cheaper on both: 8.3× input, 17× output.
Where to run it
3 hosts
GPT-5.1-Codex1 host
Per million tokens. Prices and uptime via OpenRouter, checked 11 Sep 2026.
Writing DNA
Style Comparison
Similarity
55%
GPT-4o mini uses 2.1x more hedging
GPT-4o mini
GPT-5.1-Codex
53%Vocabulary70%
19wSentence Length17w
0.82Hedging0.39
4.0Bold3.4
3.7Lists3.5
0.00Emoji0.00
1.04Headings0.50
0.22Transitions0.38
Based on 24 + 14 text responses
Research
What we learned reading every model
FAQ
Common questions
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