Grok 4 Fast ≤128k vs Gemini 2.5 Flash Preview (09-2025)
Side-by-side comparison of pricing and capabilities
Grok 4 Fast ≤128k
Gemini 2.5 Flash Preview (09-2025)
Input Price Comparison
| Attribute | Grok 4 Fast ≤128k | Gemini 2.5 Flash Preview (09-2025) |
|---|---|---|
| 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 | chat | chat |
| Status | current | preview |
Capability Comparison
| Capability | Grok 4 Fast ≤128k | Gemini 2.5 Flash Preview (09-2025) |
|---|---|---|
| coding | ||
| vision | ||
| multilingual |
Which should you choose?
Budget-conscious: Grok 4 Fast ≤128k is 33% cheaper on input tokens ($0.2 vs $0.3 per 1M tokens).
Context-heavy tasks: Gemini 2.5 Flash Preview (09-2025) offers a larger context window (1.0M vs 131K), making it better for long documents or conversations.
Capability fit: Grok 4 Fast ≤128k supports 1 capabilities (coding), while Gemini 2.5 Flash Preview (09-2025) supports 3 (coding, vision, multilingual).
Frequently Asked Questions
Which is cheaper: Grok 4 Fast ≤128k or Gemini 2.5 Flash Preview (09-2025)?
Grok 4 Fast ≤128k costs $0.2/1M input vs Gemini 2.5 Flash Preview (09-2025) at $0.3/1M input. Grok 4 Fast ≤128k is 33% cheaper on input tokens.
How do output prices compare between Grok 4 Fast ≤128k and Gemini 2.5 Flash Preview (09-2025)?
Grok 4 Fast ≤128k output: $0.5/1M, Gemini 2.5 Flash Preview (09-2025) output: $2.5/1M. Grok 4 Fast ≤128k is more economical for generation-heavy workloads.
What is Grok 4 Fast ≤128k best used for?
Grok 4 Fast ≤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 Preview (09-2025) best used for?
Gemini 2.5 Flash Preview (09-2025) is suited for complex reasoning, analysis, and tasks that benefit from its coding and vision capabilities.