LLM Comparison
Grok 4 Fast vs Sonar Reasoning Pro
Side-by-side specs, pricing & capabilities · Updated May 2026
Add to comparison
2/6 modelsSame tier:
| Organization | ||
| OpenTools Score | 44 8.8 | |
| Family | Grok | Sonar |
| Status | Current | Current |
| Release Date | Sep 2025 | Mar 2025 |
| Context Window | 2.0M tokens | 128K tokens |
| Input Price | $0.20/M tokens | $2.00/M tokens |
| Output Price | $0.50/M tokens | $8.00/M tokens |
| Pricing Notes | Cache read: $0.0500/M tokens | — |
| Capabilities | textvisioncode | textvisioncodeextended-thinking |
| Max Output | 30K tokens | — |
| API Identifier | x-ai/grok-4-fast | perplexity/sonar-reasoning-pro |
| Benchmarks | ||
| GPQA Diamond | — | 62.3perplexity |
| MATH-500 | — | 92.1perplexity |
| AIME | — | 77perplexity |
| MMLU Pro | — | 79perplexity |
| View Grok 4 Fast | View Sonar Reasoning Pro | |
Cost Calculator
Enter your expected monthly token usage to compare costs.
| Model | Input | Output | Total / mo | vs Best |
|---|---|---|---|---|
| Grok 4 FastCheapest | $0.20 | $0.25 | $0.45 | — |
| Sonar Reasoning Pro | $2.00 | $4.00 | $6.00 | +1233% |
xAI
Grok 4 Fast
Grok 4 Fast is a multimodal llm from xAI. Supports up to 2,000,000 token context window. Available from $0.20/M input tokens.
Perplexity AI
Sonar Reasoning Pro
Sonar Reasoning Pro is a multimodal llm from Perplexity AI. Supports up to 128,000 token context window. Achieves 83.0% on MMLU. Available from $2.00/M input tokens.
More Comparisons
Looking for more AI models?
Browse All LLMs