What is Deep Reasoning?
Deep reasoning (sometimes called "thinking mode" or "extended thinking") is a special mode where the AI takes extra time to work through complex problems step by step before giving you an answer. Instead of responding instantly, it reasons through the logic, considers edge cases, and checks its own work. The result is significantly more accurate answers for hard problems, at the cost of a longer wait.
Common use cases- Solving multi step math, logic, or coding problems that require careful reasoning
- Analyzing complex documents where the AI needs to cross reference multiple sections
- Making decisions that involve weighing several factors or trade offs
Step 1: Plan
Claude analyzes the problem and creates a reasoning strategy
Step 2: Consider
Explores multiple approaches and evaluates alternatives
Step 3: Check
Reviews reasoning for errors, contradictions, and edge cases
Step 4: Refine
Incorporates insights into a polished final response
Accuracy jump on hard reasoning problems
🧠
~50%
Without
Standard mode
🚀
~90%+
With
Extended thinking
What does this accuracy jump mean?
On difficult reasoning problems (complex math, multi step logic, scientific analysis), Claude goes from getting about half the answers right to getting nine out of ten right when extended thinking is enabled. The improvement is most dramatic on problems that require working through multiple steps or considering several possibilities before arriving at an answer.
🧮Complex math and logic problems
🔗Multi step reasoning chains
⚖️Analyzing conflicting information
📝Long prompts with many requirements
| Claude | OpenAI o1/o3 | Gemini Deep Think | |
|---|---|---|---|
| Approach | Built into existing models | Separate reasoning models | Multi step planning system |
| Min. plan | Pro ($20/mo) | Plus ($20/mo) | Ultra ($249.99/mo) |
| Context window | 200K tokens (~500 pages) | 128K tokens (~300 pages) | 1M tokens (~2,500 pages) |
| Strength | Writing + reasoning combined | Math and coding benchmarks | Academic benchmarks |
Most accessible reasoning option
Claude's extended thinking is available on all paid plans starting at $20/month, making it the most accessible deep reasoning option among the three major AI providers.