A paragraph is a group of sentences that form a single idea.

A good paragraph contains a topic sentence, support sentences and a concluding sentence. The topic sentence states the main point and it is the first sentence of the paragraph.

An essay consists of:

• The introduction that ends in a thesis statement (3-5 sentences). 
• The body paragraph is composed of 12-15 sentences,
• The conclusion of 12-15 sentences. 

The introduction aims to capture the audience's attention, to provide background on the topic and to guide the reader through the thesis. The usual way of how to start an essay is explained as the following: provide a general statement, begin with a fact, ask a question, use a quotation and provide a definition.

Types of paragraphs and essay

There are several types of paragraphs and essays. The most common are descriptive forms to describe something and explain to the audience a thing, person or a situation. In the narrative essay, a story is presented. In the expository essay, something is explained or there are instructions provided. A persuasive essay explains a specific point of view or describes the writer’s position.

The support sentences form the body paragraph and their usual number is 8-10 sentences. They aim to develop the main point by using examples and illustrations, citing data such as facts, statistics, evidence, details etc. They usually use quotations and paraphrasing, an anecdote or story, compare and contrast method and evaluate causes, reasons and consequences chronologically.

The concluding sentence summarizes and restates the main idea.

Each paragraph is composed of certain elements. Unity refers to the idea that has a claim and supports that thesis. Coherence is the organization and logic of a piece of writing and adds precision and quality in a thesis as well as supporting arguments. Transitions words are used to connect sentences: however, furthermore, as a result, in fact, yet, finally, meanwhile et.

There is a minimum limit of well-structured paragraphs in a good essay. In case of a majority of college essays, the requirements are 3-5 paragraphs.  The essay consists of 3 parts: an introduction, the body paragraph and a conclusion. For example, in a 250-word essay, 3 well-written paragraphs are usually necessary.

The most common essay requirements are as follows:

• 500-word essay consisting of 3-4 paragraphs,
• 800-word essay consisting of 4-8 paragraphs,
• 1000 word essay consisting of5-10 paragraphs,
• 2000 word essay consisting of 10-20 paragraphs, etc.

The number of paragraphs and an essay length depends on the type of written task as well. For example, in the case of a reflective and expository essay, there is a need for a variable number of paragraphs. 

The instructions for writing an essay are usually provided by teachers or mentors. There is frequently a part included with stated instructions for writing as well as grading rubric (A-grade and D-grade essay marks).  In most cases, the number of sentences is limited per paragraph.