Grok 4 Fast Reasoning ≤128k vs Gemini 2.5 Flash
Side-by-side comparison of pricing and capabilities
Grok 4 Fast Reasoning ≤128k
Gemini 2.5 Flash
Input Price Comparison
| Attribute | Grok 4 Fast Reasoning ≤128k | Gemini 2.5 Flash |
|---|---|---|
| Provider | xAI | |
| Input Price | $0.2 /1M tokens | $0.3 /1M tokens |
| Output Price | $0.5 /1M tokens | $2.5 /1M tokens |
| Cached Input | $0.050 /1M tokens | $0.030 /1M tokens |
| Context Window | 131K | 1.0M |
| Type | reasoning | chat |
| Status | current | current |
Capability Comparison
| Capability | Grok 4 Fast Reasoning ≤128k | Gemini 2.5 Flash |
|---|---|---|
| reasoning | ||
| coding | ||
| vision | ||
| multilingual |
Which should you choose?
Budget-conscious: Grok 4 Fast Reasoning ≤128k is 33% cheaper on input tokens ($0.2 vs $0.3 per 1M tokens).
Context-heavy tasks: Gemini 2.5 Flash offers a larger context window (1.0M vs 131K), making it better for long documents or conversations.
Capability fit: Grok 4 Fast Reasoning ≤128k supports 1 capabilities (reasoning), while Gemini 2.5 Flash supports 3 (coding, vision, multilingual).
Frequently Asked Questions
Which is cheaper: Grok 4 Fast Reasoning ≤128k or Gemini 2.5 Flash?
Grok 4 Fast Reasoning ≤128k costs $0.2/1M input vs Gemini 2.5 Flash at $0.3/1M input. Grok 4 Fast Reasoning ≤128k is 33% cheaper on input tokens.
How do output prices compare between Grok 4 Fast Reasoning ≤128k and Gemini 2.5 Flash?
Grok 4 Fast Reasoning ≤128k output: $0.5/1M, Gemini 2.5 Flash output: $2.5/1M. Grok 4 Fast Reasoning ≤128k is more economical for generation-heavy workloads.
What is Grok 4 Fast Reasoning ≤128k best used for?
Grok 4 Fast Reasoning ≤128k is best for budget-conscious applications, high-volume chatbots, and tasks where cost efficiency is the primary concern.
What is Gemini 2.5 Flash best used for?
Gemini 2.5 Flash is suited for complex reasoning, analysis, and tasks that benefit from its coding and vision capabilities.