Gemini 3.8 Live Extended Thinking vs Grok 4.1 Fast
Pricing verdict: Gemini 3.8 Live Extended Thinking vs Grok 4.1 Fast: Grok 4.1 Fast is cheaper for input-heavy usage ($0.20/M vs $0.75/M input tokens), while Grok 4.1 Fast is better for long-context tasks (2,000,000 tokens).
Direct answer: choose Grok 4.1 Fast for lower token spend and choose Grok 4.1 Fast when your workload needs longer context.
Compare API pricing, input and output token costs, context windows, and monthly estimates on one page so you can pick the right model fast.
Cost Comparison (1000 input + 500 output tokens, 100 requests/day)
Gemini 3.8 Live Extended Thinking
Grok 4.1 Fast
Cost Differences
Grok 4.1 Fast costs less than Gemini 3.8 Live Extended Thinking
Quick Recommendation
Winner for direct API pricing: Grok 4.1 Fast. At the default workload, Grok 4.1 Fast saves about $7.65/month ($93.075/year) versus Gemini 3.8 Live Extended Thinking.
Feature Comparison
| Feature | Gemini 3.8 Live Extended Thinking | Grok 4.1 Fast |
|---|---|---|
| Provider | xAI | |
| Input Price | $0.75/1M tokens | $0.20/1M tokens |
| Output Price | $4.50/1M tokens | $0.50/1M tokens |
| Context Window | 131,072 tokens | 2,000,000 tokens |
| Max Output | 65,536 tokens | 131,072 tokens |
| Category | reasoning | efficient |
| Capabilities | textvisionaudiovideoreasoningstreaming | textreasoningcode |
| Release Date | 9/15/2026 | 1/15/2026 |
Gemini 3.8 Live Extended Thinking vs Grok 4.1 Fast: Which Should You Choose?
Choosing between Gemini 3.8 Live Extended Thinking and Grok 4.1 Fast depends on your priorities: cost efficiency, context length, or raw capability. Grok 4.1 Fast is the more affordable option at $0.20/1M input tokens — 73% cheaper than Gemini 3.8 Live Extended Thinking. Meanwhile, Grok 4.1 Fast offers a significantly larger context window at 2,000,000 tokens vs 131,072 for Gemini 3.8 Live Extended Thinking.
These models come from different providers — Google and xAI — which means different API ecosystems, SDKs, rate limits, and terms of service. If you're already integrated with Google, switching to xAIinvolves migration effort beyond just pricing. Factor in your existing infrastructure when deciding.
These models target different tiers: Gemini 3.8 Live Extended Thinking is a reasoning model while Grok 4.1 Fast is efficient. This means they're optimized for different workloads. Gemini 3.8 Live Extended Thinking is built for complex tasks that require deeper reasoning, while Grok 4.1 Fast offers better value for routine operations.
Output costs matter too. Gemini 3.8 Live Extended Thinking charges $4.50/1M output tokens vs $0.50 for Grok 4.1 Fast. For generation-heavy workloads (content creation, code generation, summarization), output pricing often dominates your bill. Grok 4.1 Fast has the edge here at $0.50/1M output tokens.
Multimodal capabilities: Gemini 3.8 Live Extended Thinking supports vision (image inputs) while Grok 4.1 Fast is text-only. If your application needs image understanding, this narrows your choice.
Best Use Cases
Choose Gemini 3.8 Live Extended Thinking when:
- • You need more capabilities (vision, audio, video, streaming)
- • You're already using Google's API ecosystem
Choose Grok 4.1 Fast when:
- • Budget is a primary concern
- • You need a larger context window (2,000,000 tokens)
- • You need longer outputs (up to 131,072 tokens)
- • You're already using xAI's API ecosystem
- • You're running high-volume, latency-sensitive workloads
Pros and Caveats at a Glance
Gemini 3.8 Live Extended Thinking
- • Input pricing: $0.75/M tokens
- • Output pricing: $4.50/M tokens
- • Context window: 131,072 tokens
- • Max output: 65,536 tokens
Watch out for
- • Higher input cost than Grok 4.1 Fast
- • Higher output cost than Grok 4.1 Fast
- • Smaller context window than Grok 4.1 Fast
Grok 4.1 Fast
- • Input pricing: $0.20/M tokens
- • Output pricing: $0.50/M tokens
- • Context window: 2,000,000 tokens
- • Max output: 131,072 tokens
Watch out for
- • Trade-offs are minor in this matchup.
Try Different Scenarios
Use the calculator below to see how costs change with different usage patterns
Gemini 3.8 Live Extended Thinking (Google)
Grok 4.1 Fast (xAI)
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Which is cheaper, Gemini 3.8 Live Extended Thinking or Grok 4.1 Fast?▼
What is the context window difference between Gemini 3.8 Live Extended Thinking and Grok 4.1 Fast?▼
Which model is better for AI Chatbot?▼
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Where can I compare Google and xAI API pricing beyond this model matchup?▼
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