GPT-5.1 Codex mini vs Grok 4 Fast >128k
Side-by-side comparison of pricing and capabilities
GPT-5.1 Codex mini
Grok 4 Fast >128k
Input Price Comparison
| Attribute | GPT-5.1 Codex mini | Grok 4 Fast >128k |
|---|---|---|
| Provider | OpenAI | xAI |
| Input Price | $0.25 /1M tokens | $0.4 /1M tokens |
| Output Price | $2 /1M tokens | $1 /1M tokens |
| Cached Input | $0.025 /1M tokens | $0.050 /1M tokens |
| Context Window | 400K | 1.0M |
| Type | chat | chat |
| Status | current | current |
Capability Comparison
| Capability | GPT-5.1 Codex mini | Grok 4 Fast >128k |
|---|---|---|
| coding |
Which should you choose?
Budget-conscious: GPT-5.1 Codex mini is 38% cheaper on input tokens ($0.25 vs $0.4 per 1M tokens).
Context-heavy tasks: Grok 4 Fast >128k offers a larger context window (1.0M vs 400K), making it better for long documents or conversations.
Capability fit: GPT-5.1 Codex mini supports 1 capabilities (coding), while Grok 4 Fast >128k supports 1 (coding).
Frequently Asked Questions
Which is cheaper: GPT-5.1 Codex mini or Grok 4 Fast >128k?
GPT-5.1 Codex mini costs $0.25/1M input vs Grok 4 Fast >128k at $0.4/1M input. GPT-5.1 Codex mini is 38% cheaper on input tokens.
How do output prices compare between GPT-5.1 Codex mini and Grok 4 Fast >128k?
GPT-5.1 Codex mini output: $2/1M, Grok 4 Fast >128k output: $1/1M. Grok 4 Fast >128k is more economical for generation-heavy workloads.
What is GPT-5.1 Codex mini best used for?
GPT-5.1 Codex mini is best for budget-conscious applications, high-volume chatbots, and tasks where cost efficiency is the primary concern.
What is Grok 4 Fast >128k best used for?
Grok 4 Fast >128k is suited for complex reasoning, analysis, and tasks that benefit from its coding capabilities.