¶Three to five sentences is a good guideline, but the sentences should all relate to each other in the same event/action/description.
Shorter paragraphs tend to be more readable on smaller electronic devices.
For most paper books and magazines, the first line of each new paragraph should be indented. Paragraphs should immediately follow each other with no blank line between.
Online stories/articles/posts do not usually indent the first line. Instead, as in this post and many others you will find, a blank line follows each paragraph.
Starting a new paragraph lets the reader know that a different person is speaking.
Examples from “The Calling of Dan Matthews” by Harold Bell Wright:
The Elder proceeded, “They used to tell us some great stories about your father, too. Big man, isn’t he?”
“Yes, sir, fairly good size.”
“Yes, I remember some of his fights we used to hear about; and there was another member of the family, they mentioned a good deal. Dad—Dad—”
“Howitt,” said Dan softly.
“That’s it, Howitt. A kind of a shepherd, wasn’t he?”
Example (paragraphs are shortened to save blog space and reader time)
“Let me explain what happened.” Joseph sat up straighter.
“First, when we motored out to the middle of the lake, the sun was shining. There were a few clouds, but nothing scary. We hadn’t been out for ten minutes when …
“Then the boat began to sink …
“We paddled furiously, trying to …
“Jeremiah found a hole and stuffed …
“Fortunately, with that minor repair, …”
He sank back into his chair.
(Each paragraph has an opening quotation mark. The closing quotation mark is only at the end of the last paragraph of what is spoken.)
Readers prefer (especially on smaller devices) shorter paragraphs to longer ones. A paragraph that takes up an entire page will slow down the reader. Too many long paragraphs will discourage the reader.
With indentation, no extra line is placed between paragraphs. Most books are written in this style.
Only a few scattered clouds dotted the blue sky when they shoved off in their fishing boat. The water parted in front of them, trailing only a slight wake. Joseph pointed the bow toward his favorite fishing place.
Jeremiah dug through his tackle box, looking for the appropriate lure. With it attached, he waited.
Not far off, a fish jumped.
“Aha! They’re ready for us.” Joseph cut the motor.
They set their lines, grabbed a couple of beers, and relaxed.
This takes more space, as a blank line is added after each paragraph. Business correspondence often uses this style.
Thank you for your interest in our new gadget designed to wash your dishes remotely. We have spent many hours in its development.
Your question was how remote “remotely” means.
Our earliest version of WYDR (“Wash Your Dishes Remotely”) required the person to be located within a distance of no more than 300 feet. That was convenient for anyone still in the house or in a back or front yard.
The newer WYDR allowed the person with the remote control to be within a mile of the device, allowing someone who forgot to turn on the dishwasher to operate it from well beyond the driveway.
Our newest control, with the help of NASA, allows the operator to start the dishwashing process from any planet in the solar system. While this may seem like an extravagant claim, we have tested it from the International Space Station. Please inform us if you are going beyond that.
If you have further questions, feel free to call us at (555) 555-5555.
Length of sentences in a paragraph
Varying their length and style keeps the reader interested. However, a long and complicated sentence may create a maze difficult to escape.
The Calling of Dan Matthews by Harold Bell Wright.
(1) Corinth was in the midst of a street fair. (2) The neighboring city held a street fair that year, therefore Corinth.(3) All that the city does Corinth imitates, thereby with a beautiful rural simplicity thinking herself metropolitan, just as those who take their styles from the metropolitan feel themselves well dressed.(4) The very Corinthian clerks and grocery boys, lodging behind their counters and in the doorways, the lawyer’s understudy with his feet on the window sill, the mechanic’s apprentice, the high school youths and the local sporting fraternity—all imitated their city kind and talked smartly about the country “rubes” who came to town; never once dreaming that they themselves, when they “go to town,” are as much a mark for the like wit of their city brothers. (5) So Corinth was in the midst of a street fair.
(The first three sentences vary in their length and style. Sentence (4), while descriptive, is long and complicated. A reader might well have to read it several times to follow its meaning to the end.)