Gemini 2.5 Pro vs Grok 4-20
Complete pricing and performance comparison between Google's Gemini 2.5 Pro and xAI's Grok 4-20.
Quick Verdict
Cheaper
Gemini 2.5 Pro (input) / Grok 4-20 (output)
Input: 1.6x diff, Output: 1.7x diff
Larger Context
Gemini 2.5 Pro
1.0M vs 131K
Higher Quality
Grok 4-20
Score: 49 vs 35
Faster
Gemini 2.5 Pro
124 vs 101 tok/s
Pricing Comparison
| Spec | Gemini 2.5 Pro | Grok 4-20 | Difference |
|---|---|---|---|
| Provider | xAI | ||
| Input / 1M tokens | $1.25 | $2 | Gemini 2.5 Pro is 38% more expensive |
| Output / 1M tokens | $10 | $6 | Grok 4-20 is 40% more expensive |
| Context Window | 1.0M | 131K | 8x difference |
| Max Output | 66K | 16K |
Performance Benchmarks
| Metric | Gemini 2.5 Pro | Grok 4-20 | Winner |
|---|---|---|---|
| Quality Index | 35 | 49 | Grok 4-20 |
| Output Speed | 124 tok/s | 101 tok/s | Gemini 2.5 Pro |
| Time to First Token | 21.40s | 20.69s | Grok 4-20 |
| Value (Quality/$) | 27.7 | 24.3 | 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 Pro | Grok 4-20 | Savings |
|---|---|---|---|
Single request 1K in / 300 out | $0.0042 | $0.0038 | Same |
10 requests 10K in / 3K out | $0.042 | $0.038 | Grok 4-20 saves $0.0045 |
100 requests 100K in / 30K out | $0.425 | $0.380 | Grok 4-20 saves $0.045 |
1,000 requests 1M in / 300K out | $4.25 | $3.80 | Grok 4-20 saves $0.450 |
10,000 requests 10M in / 3M out | $42.50 | $38.00 | Grok 4-20 saves $4.50 |
1M requests/mo 1B in / 300M out | $4250.00 | $3800.00 | Grok 4-20 saves $450.00 |
Pros & Cons
Gemini 2.5 Pro Strengths
- +Cheaper input tokens
- +Larger context window (1.0M vs 131K)
- +Higher max output tokens
- +Faster output (124 vs 101 tok/s)
Grok 4-20 Strengths
- +Cheaper output tokens
- +Higher quality score (49 vs 35)
- +Lower latency (faster first token)
When to Use Each Model
Choose Gemini 2.5 Pro for
- →Long documents, large codebases, or multi-turn conversations
- →Generating long-form content or detailed code
- →Real-time applications, chat, or autocomplete
Choose Grok 4-20 for
- →Tasks requiring maximum accuracy and reasoning
Frequently Asked Questions
Which is cheaper, Gemini 2.5 Pro or Grok 4-20?
For input tokens, Gemini 2.5 Pro is 1.6x cheaper at $1.25/1M tokens. For output tokens, Grok 4-20 is 1.7x cheaper at $6/1M tokens. At typical usage (1M input + 300K output), Gemini 2.5 Pro costs $4.25 vs Grok 4-20 at $3.80.
What's the context window difference?
Gemini 2.5 Pro supports 1.0M context (1,048,576 tokens), while Grok 4-20 supports 131K (131,072 tokens). Gemini 2.5 Pro can handle 8x more context in a single request.
Which model has better benchmarks?
Quality Index: Gemini 2.5 Pro scores 35 vs Grok 4-20 at 49. Speed: Gemini 2.5 Pro generates 124 tok/s vs Grok 4-20 at 101 tok/s. Time to first token: Gemini 2.5 Pro at 21.40s vs Grok 4-20 at 20.69s.
When should I choose Gemini 2.5 Pro over Grok 4-20?
Choose Gemini 2.5 Pro when you need: Cheaper input tokens, Larger context window (1.0M vs 131K), Higher max output tokens, Faster output (124 vs 101 tok/s). Choose Grok 4-20 when you need: Cheaper output tokens, Higher quality score (49 vs 35), Lower latency (faster first token).
How much would 10,000 API requests cost?
At 1K input + 300 output tokens per request (typical chat): Gemini 2.5 Pro = $42.50, Grok 4-20 = $38.00. At 10K input + 1K output per request (longer conversations): Gemini 2.5 Pro = $225.00, Grok 4-20 = $260.00.
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