The English time adverbials in time and on time are often confused when used. Although they sound similar, they have slightly different meanings. For details of where they can appear in a sentence, see adverbials of indefinite time and the grammatical modifier. Compare their usage and the sense they express in the following examples:

• The expression ‘in time’ is used in the sense of ‘early enough’, which means that there is still some time left:
  • “Will you be ready in time for the meeting?”
  • “I’m awaiting a letter. I hope it will get here in time before the holidays.”
  • “I’m playing tennis this afternoon. I want to be there in time to change.”
  • Information: ‘just in time’ is also often utilised, which means ‘nearly too late’:
    • “I got to the airport just in time to catch my flight.”
• On the other hand, the phrase ‘on time’ is employed in the sense of ‘punctual’ and refers to a specific point in time, e.g., a time of day:
  • “The next train leaves on time at one o’clock.”
  • “Peter is very reliable. He’s always on time.”
  • “Let’s meet at 11.30 and be there on time, please. This time, I won’t wait.”

The following exercises and explanations refer to the use and difference of ‘in time’ and ‘on time’ in English grammar and may also train your skills:

• Using adverbs in English grammar
• Use and difference of ‘in the end’ and ‘at the end’
• Adverbials in English grammar
• Exercise 1: ‘in/on time’