What is the difference between sentence, paragraph, and section chunking?

Sentence chunking gives very precise retrieval but loses all surrounding context, often producing passages too short to be useful. Paragraph chunking balances precision and context, matching how humans naturally organize ideas. Section chunking, splitting on headings or chapter markers, preserves topical coherence but produces uneven chunk sizes. Most production systems use a hybrid: recursive splitting that prefers paragraph boundaries, falls back to sentences when paragraphs exceed token limits, and keeps section headers as metadata.