Run-on Sentences and Sentence Fragments

We hope you find our self-editing tools helpful!
If you ever find you're too busy to spend the time editing your own work, let us fix it for you! To speak with a Boston Editor about your document or project, call (617) 279-0019.
What is a Run-on Sentence?

A run-on sentence is made up of two or more complete ideas that are joined without punctuation.


Readability studies show that sentences of fewer than 20 words are best for comprehension, with an average sentence consisting of 15 to 17 words.




In this exercise, you will be presented with a series of screens where you'll see three descriptions of store concepts like the one shown below in which some aspects may be similar, but each of the three concepts will be different, so please compare them carefully. 


To identify run-on sentences:

  • Count the number of words, and shorten longer sentences.
  • Read the sentence out loud to hear the pace and rhythm.
  • Go on a “which hunt”. Run-ons sometimes happen when “which” combines ideas.
  • In compound sentences (sentences containing 2 or more complete thoughts), read each of the compound ideas separately, and check for flow, relationship, and logic.

What is a Sentence Fragment?


A seAn incomplete thought that starts with a capital letter and ends with a period.




Because you may have contacted us at a busy time.


To identify sentence fragments:

  • Read the sentence out loud to see if you are “left hanging” at the end.
  • Avoid starting sentences with Because, And, and But