Gemini 3.1 Pro vs Grok 4-20
Complete pricing and performance comparison between Google's Gemini 3.1 Pro and xAI's Grok 4-20.
Quick Verdict
Cheaper
Gemini 3.1 Pro (input) / Grok 4-20 (output)
Input: 1.0x diff, Output: 2.0x diff
Larger Context
Gemini 3.1 Pro
1.0M vs 131K
Higher Quality
Gemini 3.1 Pro
Score: 57 vs 49
Faster
Gemini 3.1 Pro
120 vs 101 tok/s
Pricing Comparison
| Spec | Gemini 3.1 Pro | Grok 4-20 | Difference |
|---|---|---|---|
| Provider | xAI | ||
| Input / 1M tokens | $2 | $2 | Same |
| Output / 1M tokens | $12 | $6 | Grok 4-20 is 50% more expensive |
| Context Window | 1.0M | 131K | 8x difference |
| Max Output | 66K | 16K |
Performance Benchmarks
| Metric | Gemini 3.1 Pro | Grok 4-20 | Winner |
|---|---|---|---|
| Quality Index | 57 | 49 | Gemini 3.1 Pro |
| Output Speed | 120 tok/s | 101 tok/s | Gemini 3.1 Pro |
| Time to First Token | 21.32s | 20.69s | Grok 4-20 |
| Value (Quality/$) | 28.6 | 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 3.1 Pro | Grok 4-20 | Savings |
|---|---|---|---|
Single request 1K in / 300 out | $0.0056 | $0.0038 | Grok 4-20 saves $0.0018 |
10 requests 10K in / 3K out | $0.056 | $0.038 | Grok 4-20 saves $0.018 |
100 requests 100K in / 30K out | $0.560 | $0.380 | Grok 4-20 saves $0.180 |
1,000 requests 1M in / 300K out | $5.60 | $3.80 | Grok 4-20 saves $1.80 |
10,000 requests 10M in / 3M out | $56.00 | $38.00 | Grok 4-20 saves $18.00 |
1M requests/mo 1B in / 300M out | $5600.00 | $3800.00 | Grok 4-20 saves $1800.00 |
Pros & Cons
Gemini 3.1 Pro Strengths
- +Larger context window (1.0M vs 131K)
- +Higher max output tokens
- +Faster output (120 vs 101 tok/s)
- +Higher quality score (57 vs 49)
Grok 4-20 Strengths
- +Cheaper output tokens
- +Lower latency (faster first token)
When to Use Each Model
Choose Gemini 3.1 Pro for
- →Long documents, large codebases, or multi-turn conversations
- →Generating long-form content or detailed code
- →Tasks requiring maximum accuracy and reasoning
- →Real-time applications, chat, or autocomplete
Choose Grok 4-20 for
- →Projects already integrated with xAI's ecosystem
Frequently Asked Questions
Which is cheaper, Gemini 3.1 Pro or Grok 4-20?
For input tokens, Gemini 3.1 Pro is 1.0x cheaper at $2/1M tokens. For output tokens, Grok 4-20 is 2.0x cheaper at $6/1M tokens. At typical usage (1M input + 300K output), Gemini 3.1 Pro costs $5.60 vs Grok 4-20 at $3.80.
What's the context window difference?
Gemini 3.1 Pro supports 1.0M context (1,048,576 tokens), while Grok 4-20 supports 131K (131,072 tokens). Gemini 3.1 Pro can handle 8x more context in a single request.
Which model has better benchmarks?
Quality Index: Gemini 3.1 Pro scores 57 vs Grok 4-20 at 49. Speed: Gemini 3.1 Pro generates 120 tok/s vs Grok 4-20 at 101 tok/s. Time to first token: Gemini 3.1 Pro at 21.32s vs Grok 4-20 at 20.69s.
When should I choose Gemini 3.1 Pro over Grok 4-20?
Choose Gemini 3.1 Pro when you need: Larger context window (1.0M vs 131K), Higher max output tokens, Faster output (120 vs 101 tok/s), Higher quality score (57 vs 49). Choose Grok 4-20 when you need: Cheaper output tokens, Lower latency (faster first token).
How much would 10,000 API requests cost?
At 1K input + 300 output tokens per request (typical chat): Gemini 3.1 Pro = $56.00, Grok 4-20 = $38.00. At 10K input + 1K output per request (longer conversations): Gemini 3.1 Pro = $320.00, Grok 4-20 = $260.00.