Gemini 2.5 Flash vs Grok 4
Complete pricing and performance comparison between Google's Gemini 2.5 Flash and xAI's Grok 4.
Quick Verdict
Cheaper
Gemini 2.5 Flash
10.0x cheaper input, 6.0x cheaper output
Larger Context
Grok 4
2.0M vs 1.0M
Higher Quality
Grok 4
Score: 42 vs 21
Faster
Gemini 2.5 Flash
231 vs 55 tok/s
Pricing Comparison
| Spec | Gemini 2.5 Flash | Grok 4 | Difference |
|---|---|---|---|
| Provider | xAI | ||
| Input / 1M tokens | $0.3 | $3 | Gemini 2.5 Flash is 90% more expensive |
| Output / 1M tokens | $2.5 | $15 | Gemini 2.5 Flash is 83% more expensive |
| Context Window | 1.0M | 2.0M | 2x difference |
| Max Output | 66K | 16K |
Performance Benchmarks
| Metric | Gemini 2.5 Flash | Grok 4 | Winner |
|---|---|---|---|
| Quality Index | 21 | 42 | Grok 4 |
| Output Speed | 231 tok/s | 55 tok/s | Gemini 2.5 Flash |
| Time to First Token | 0.42s | 9.76s | Gemini 2.5 Flash |
| Value (Quality/$) | 68.7 | 13.8 | Higher = better value |
Benchmark data from Artificial Analysis. Quality Index is a composite score across reasoning, coding, and knowledge tasks.
Cost at Scale
Estimated cost at different usage levels (3:1 input-to-output token ratio, typical for chat).
| Usage | Gemini 2.5 Flash | Grok 4 | Savings |
|---|---|---|---|
Single request 1K in / 300 out | $0.0010 | $0.0075 | Gemini 2.5 Flash saves $0.0065 |
10 requests 10K in / 3K out | $0.010 | $0.075 | Gemini 2.5 Flash saves $0.065 |
100 requests 100K in / 30K out | $0.105 | $0.750 | Gemini 2.5 Flash saves $0.645 |
1,000 requests 1M in / 300K out | $1.05 | $7.50 | Gemini 2.5 Flash saves $6.45 |
10,000 requests 10M in / 3M out | $10.50 | $75.00 | Gemini 2.5 Flash saves $64.50 |
1M requests/mo 1B in / 300M out | $1050.00 | $7500.00 | Gemini 2.5 Flash saves $6450.00 |
Pros & Cons
Gemini 2.5 Flash Strengths
- +Cheaper input tokens
- +Cheaper output tokens
- +Higher max output tokens
- +Faster output (231 vs 55 tok/s)
- +Lower latency (faster first token)
Grok 4 Strengths
- +Larger context window (2.0M vs 1.0M)
- +Higher quality score (42 vs 21)
When to Use Each Model
Choose Gemini 2.5 Flash for
- →Budget-conscious projects where cost is the primary factor
- →Generating long-form content or detailed code
- →Real-time applications, chat, or autocomplete
Choose Grok 4 for
- →Long documents, large codebases, or multi-turn conversations
- →Tasks requiring maximum accuracy and reasoning
Frequently Asked Questions
Which is cheaper, Gemini 2.5 Flash or Grok 4?
For input tokens, Gemini 2.5 Flash is 10.0x cheaper at $0.3/1M tokens. For output tokens, Gemini 2.5 Flash is 6.0x cheaper at $2.5/1M tokens. At typical usage (1M input + 300K output), Gemini 2.5 Flash costs $1.05 vs Grok 4 at $7.50.
What's the context window difference?
Gemini 2.5 Flash supports 1.0M context (1,048,576 tokens), while Grok 4 supports 2.0M (2,000,000 tokens). Grok 4 can handle 2x more context in a single request.
Which model has better benchmarks?
Quality Index: Gemini 2.5 Flash scores 21 vs Grok 4 at 42. Speed: Gemini 2.5 Flash generates 231 tok/s vs Grok 4 at 55 tok/s. Time to first token: Gemini 2.5 Flash at 0.42s vs Grok 4 at 9.76s.
When should I choose Gemini 2.5 Flash over Grok 4?
Choose Gemini 2.5 Flash when you need: Cheaper input tokens, Cheaper output tokens, Higher max output tokens, Faster output (231 vs 55 tok/s), Lower latency (faster first token). Choose Grok 4 when you need: Larger context window (2.0M vs 1.0M), Higher quality score (42 vs 21).
How much would 10,000 API requests cost?
At 1K input + 300 output tokens per request (typical chat): Gemini 2.5 Flash = $10.50, Grok 4 = $75.00. At 10K input + 1K output per request (longer conversations): Gemini 2.5 Flash = $55.00, Grok 4 = $450.00.