Question 1

What is a "context window" and why does it matter?

Accepted Answer

The context window is the maximum number of tokens a model can process in a single call (prompt + answer). 200,000 tokens fit ~2 long PDFs; 1M fits ~10 full novels. If you're analysing contracts or large codebases you need large windows. For a support chatbot, 32K is usually plenty.

Question 2

Which provider has the largest context window?

Accepted Answer

As of April 2026, Grok 4.1 Fast leads with 2M tokens, followed by OpenAI (1.1M on GPT-5.4/Mini/Nano) and Anthropic, Google, Meta, Qwen and MiniMax all at 1M. Mistral, Perplexity and Z.AI sit between 128K and 256K. Use the "Context Windows" tool above to visualise and plug in how many tokens your own content weighs.

Question 3

What is a "reasoning model" (o3, DeepSeek R1)?

Accepted Answer

They're models trained to think step by step before answering, generating an internal chain of reasoning. Slower and pricier per token than standard models, but much better at math, logic and hard code. Use them selectively: not worth it for a customer-support bot, but great for technical analysis, debugging or autonomous agents.

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What do these numbers mean?

Frequently asked questions about AI models and pricing

What is a "context window" and why does it matter?

Which provider has the largest context window?

What is a "reasoning model" (o3, DeepSeek R1)?

What do these numbers mean?

Frequently asked questions about AI models and pricing

What is a "context window" and why does it matter?

Which provider has the largest context window?

What is a "reasoning model" (o3, DeepSeek R1)?