Gemini 3.1 Pro vs Kimi K2.5
Complete pricing and performance comparison between Google's Gemini 3.1 Pro and Moonshot's Kimi K2.5.
Quick Verdict
Cheaper
Kimi K2.5
3.3x cheaper input, 4.0x cheaper output
Larger Context
Gemini 3.1 Pro
1.0M vs 128K
Higher Quality
Gemini 3.1 Pro
Score: 57 vs 47
Faster
Gemini 3.1 Pro
120 vs 34 tok/s
Pricing Comparison
| Spec | Gemini 3.1 Pro | Kimi K2.5 | Difference |
|---|---|---|---|
| Provider | Moonshot | ||
| Input / 1M tokens | $2 | $0.6 | Kimi K2.5 is 70% more expensive |
| Output / 1M tokens | $12 | $3 | Kimi K2.5 is 75% more expensive |
| Context Window | 1.0M | 128K | 8x difference |
| Max Output | 66K | 33K |
Performance Benchmarks
| Metric | Gemini 3.1 Pro | Kimi K2.5 | Winner |
|---|---|---|---|
| Quality Index | 57 | 47 | Gemini 3.1 Pro |
| Output Speed | 120 tok/s | 34 tok/s | Gemini 3.1 Pro |
| Time to First Token | 21.32s | 1.35s | Kimi K2.5 |
| Value (Quality/$) | 28.6 | 78.0 | 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 | Kimi K2.5 | Savings |
|---|---|---|---|
Single request 1K in / 300 out | $0.0056 | $0.0015 | Kimi K2.5 saves $0.0041 |
10 requests 10K in / 3K out | $0.056 | $0.015 | Kimi K2.5 saves $0.041 |
100 requests 100K in / 30K out | $0.560 | $0.150 | Kimi K2.5 saves $0.410 |
1,000 requests 1M in / 300K out | $5.60 | $1.50 | Kimi K2.5 saves $4.10 |
10,000 requests 10M in / 3M out | $56.00 | $15.00 | Kimi K2.5 saves $41.00 |
1M requests/mo 1B in / 300M out | $5600.00 | $1500.00 | Kimi K2.5 saves $4100.00 |
Pros & Cons
Gemini 3.1 Pro Strengths
- +Larger context window (1.0M vs 128K)
- +Higher max output tokens
- +Faster output (120 vs 34 tok/s)
- +Higher quality score (57 vs 47)
Kimi K2.5 Strengths
- +Cheaper input tokens
- +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 Kimi K2.5 for
- →Budget-conscious projects where cost is the primary factor
Frequently Asked Questions
Which is cheaper, Gemini 3.1 Pro or Kimi K2.5?
For input tokens, Kimi K2.5 is 3.3x cheaper at $0.6/1M tokens. For output tokens, Kimi K2.5 is 4.0x cheaper at $3/1M tokens. At typical usage (1M input + 300K output), Gemini 3.1 Pro costs $5.60 vs Kimi K2.5 at $1.50.
What's the context window difference?
Gemini 3.1 Pro supports 1.0M context (1,048,576 tokens), while Kimi K2.5 supports 128K (128,000 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 Kimi K2.5 at 47. Speed: Gemini 3.1 Pro generates 120 tok/s vs Kimi K2.5 at 34 tok/s. Time to first token: Gemini 3.1 Pro at 21.32s vs Kimi K2.5 at 1.35s.
When should I choose Gemini 3.1 Pro over Kimi K2.5?
Choose Gemini 3.1 Pro when you need: Larger context window (1.0M vs 128K), Higher max output tokens, Faster output (120 vs 34 tok/s), Higher quality score (57 vs 47). Choose Kimi K2.5 when you need: Cheaper input tokens, 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, Kimi K2.5 = $15.00. At 10K input + 1K output per request (longer conversations): Gemini 3.1 Pro = $320.00, Kimi K2.5 = $90.00.
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