| Signal | Grok 4 Fast | Delta | Kimi K2 Thinking |
|---|---|---|---|
Capabilities | 100 | +33 | |
Benchmarks | 70 | +70 | |
Pricing | 1 | -1 | |
Context window size | 100 | +19 | |
Recency | 98 | -2 | |
Output Capacity | 75 | +55 | |
| Overall Result | 4 wins | of 6 | 2 wins |
30
days higher
0
days
0
days higher
xAI
Moonshot AI
Grok 4 Fast saves you $102.00/month
That's $1224.00/year compared to Kimi K2 Thinking at your current usage level of 100K calls/month.
| Metric | Grok 4 Fast | Kimi K2 Thinking | Winner |
|---|---|---|---|
| Overall Score | 83 | 73 | Grok 4 Fast |
| Rank | #55 | #138 | Grok 4 Fast |
| Quality Rank | #55 | #138 | Grok 4 Fast |
| Adoption Rank | #55 | #138 | Grok 4 Fast |
| Parameters | -- | -- | -- |
| Context Window | 2000K | 131K | Grok 4 Fast |
| Pricing | $0.20/$0.50/M | $0.47/$2.00/M | -- |
| Signal Scores | |||
| Capabilities | 100 | 67 | Grok 4 Fast |
| Benchmarks | 70 | -- | Grok 4 Fast |
| Pricing | 1 | 2 | Kimi K2 Thinking |
| Context window size | 100 | 81 | Grok 4 Fast |
| Recency | 98 | 100 | Kimi K2 Thinking |
| Output Capacity | 75 | 20 | Grok 4 Fast |
Our composite score (0–100) combines six weighted signals: benchmark performance (25%), pricing efficiency (25%), context window size (15%), model recency (15%), output capacity (10%), and capability versatility (10%). Here's what the scores mean for these two models:
Scores 83/100 (rank #55), placing it in the top 81% of all 290 models tracked.
Scores 73/100 (rank #138), placing it in the top 53% of all 290 models tracked.
Grok 4 Fast has a 11-point advantage, which typically translates to noticeably better performance on complex reasoning, code generation, and multi-step tasks.
Grok 4 Fast offers 72% better value per quality point. At 1M tokens/day, you'd spend $10.50/month with Grok 4 Fast vs $37.05/month with Kimi K2 Thinking - a $26.55 monthly difference.
Both models have comparable response speeds. For most applications, the latency difference is negligible.
When latency matters most: Interactive chatbots, IDE code completion, real-time translation, and user-facing applications where response time directly impacts experience. For batch processing, background summarization, or offline analysis, latency is less critical.
Code generation & review
Higher benchmark score (0/100) indicates stronger performance on coding tasks like generating functions, debugging, and refactoring
Customer support chatbot
Faster response time (speed score 0/100) is critical for user-facing chat. Grok 4 Fast also offers lower per-token costs for high-volume support
Long document analysis
Larger context window (2000K tokens) can process longer documents, contracts, and research papers in a single pass
Batch data extraction
Lower output pricing ($0.50/M) reduces costs when processing thousands of records daily
Creative writing & content
Higher overall composite score (83/100) correlates with better nuance, coherence, and style in long-form content
Image understanding & OCR
Supports vision input - can analyze screenshots, diagrams, photos, and scanned documents directly
Grok 4 Fast clearly outperforms Kimi K2 Thinking with a significant 10.5-point lead. For most general use cases, Grok 4 Fast is the stronger choice. However, Kimi K2 Thinking may still excel in niche scenarios.
Best for Quality
Grok 4 Fast
Marginally better benchmark scores; both are excellent
Best for Cost
Grok 4 Fast
72% lower pricing; better value at scale
Best for Reliability
Grok 4 Fast
Higher uptime and faster response speeds
Best for Prototyping
Grok 4 Fast
Stronger community support and better developer experience
Best for Production
Grok 4 Fast
Wider enterprise adoption and proven at scale
by xAI
| Capability | Grok 4 Fast | Kimi K2 Thinking |
|---|---|---|
| Vision (Image Input)differs | ||
| Function Calling | ||
| Streaming | ||
| JSON Mode | ||
| Reasoning | ||
| Web Searchdiffers | ||
| Image Output |
xAI
Moonshot AI
Grok 4 Fast saves you $2.29/month
That's 70% cheaper than Kimi K2 Thinking at 1,000 tokens/request and 100 requests/day.
Assumes 60% input / 40% output token ratio per request. Actual costs may vary based on your usage pattern.
| Parameter | Grok 4 Fast | Kimi K2 Thinking |
|---|---|---|
| Context Window | 2M | 131K |
| Max Output Tokens | 30,000 | -- |
| Open Source | No | Yes |
| Created | Sep 19, 2025 | Nov 6, 2025 |
Grok 4 Fast scores 83/100 (rank #55) compared to Kimi K2 Thinking's 73/100 (rank #138), giving it a 11-point advantage. Grok 4 Fast is the stronger overall choice, though Kimi K2 Thinking may excel in specific areas like certain benchmarks.
Grok 4 Fast is ranked #55 and Kimi K2 Thinking is ranked #138 out of 290+ AI models. Rankings use a composite score combining benchmark performance (25%), pricing (25%), context window (15%), recency (15%), output capacity (10%), and versatility (10%). Scores update hourly.
Grok 4 Fast is cheaper at $0.50/M output tokens vs Kimi K2 Thinking's $2.00/M output tokens - 4.0x more expensive. Input token pricing: Grok 4 Fast at $0.20/M vs Kimi K2 Thinking at $0.47/M.
Grok 4 Fast has a larger context window of 2,000,000 tokens compared to Kimi K2 Thinking's 131,072 tokens. A larger context window means the model can process longer documents and conversations.