What is Reasoning Model?
TL;DR
An AI model that executes step-by-step logical reasoning before answering. Dramatically improves accuracy on complex problems.
Reasoning Model: Definition & Explanation
A Reasoning Model is an AI model that, instead of answering immediately, performs an internal step-by-step logical reasoning process (Chain-of-Thought) before producing its final response. Examples include OpenAI's o1/o3, DeepSeek R1, and Gemini 2.5 Pro, which achieve significantly higher accuracy than conventional LLMs on complex mathematics, programming, logic puzzles, and scientific reasoning. The approach of giving the model 'thinking time' unlocks its reasoning capabilities. Since OpenAI's release of o1 in 2025, major AI companies have been racing to develop reasoning models. The emergence of DeepSeek R1 made high-performance reasoning available through open-source models, and reasoning models have become the primary battleground in the 2026 LLM competition. However, the reasoning process takes additional time, resulting in slower response speeds and higher token consumption compared to standard models.