Gemini 2.5 Flash PreviewvsGrok 4 Fast (free)
Grok 4 Fast (free) is cheaper than Gemini 2.5 Flash Preview at $0/M vs $0.15/M input tokens.
| Spec | Gemini 2.5 Flash Preview | Grok 4 Fast (free) |
|---|---|---|
| Input price | $0.15/M tokens | Free |
| Output price | $0.6/M tokens | Free |
| Context window | 1.0M tokens | 2.0M tokens |
| Parameters | Not disclosed | Not disclosed |
| Free API (OpenRouter) | No | No |
| Released | Apr 2025 | Sep 2025 |
Our Verdict
Grok 4 Fast (free)
Gemini 2.5 Flash PreviewRunner-up
Not enough votes to call it. On the specs, Grok 4 Fast (free) has the edge: bigger model tier, newer, bigger context window.
Pick Gemini 2.5 Flash Preview for Web Design. Pick Grok 4 Fast (free) for Reasoning.
Slight edge
Reviewing agent-written code?See a Brief PR report
API pricing
Cost per 1M tokens
Gemini 2.5 Flash Preview
Input
$0.15
Output
$0.60
Grok 4 Fast (free)
Input
$0.000
Output
$0.000
Writing DNA
Style Comparison
Similarity
55%
Grok 4 Fast (free) uses 17.8x more headings
Gemini 2.5 Flash Preview
Grok 4 Fast (free)
51%Vocabulary65%
15wSentence Length13w
0.70Hedging0.56
4.1Bold1.4
3.3Lists2.5
0.00Emoji0.00
0.09Headings1.58
0.24Transitions0.28
Based on 12 + 14 text responses
Research
What we learned reading every model
FAQ
Common questions
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