A paragraph typically requires about 3 to 5 sentences for proper structure and cohesion, with this range allowing enough space to introduce, develop, and conclude a central idea effectively. However, the ideal number of sentences depends on the writing context, purpose, and complexity of the topic.

Sentence Count by Writing Context

• Academic writing: Usually 5 to 8 sentences, enough to develop a complex idea with evidence and analysis.
• Digital content/blogs: Generally shorter paragraphs with 2 to 4 sentences for readability and quick scanning.
• Journalistic writing: Often 1 to 3 sentences for concise communication.
• Business writing: Typically around 3 to 5 sentences to maintain clarity and brevity.

Key Factors for Cohesion

• A paragraph should focus on a single main idea.
• Sentences within the paragraph must support and elaborate on that idea.
• Effective paragraphs include a topic sentence , multiple supporting sentences, and often a concluding sentence.
• Flexibility exists for emphasis or style, such as one-sentence paragraphs for impact, especially in digital and journalistic writing.

In sum, while 3 to 5 sentences is a strong general guideline ensuring proper paragraph structure and cohesion, the exact number varies with style, audience, and document type, with clarity and unity being the most critical goals.