Difference Between For and Since

Have you ever wondered whether to use for or since in a sentence? In English, the prepositions for and since are used to talk about time. For tells us how long something happens, while since tells us when it started. In this guide, we will learn about the difference between for and since. 

Table of Contents:

• What Is the Difference Between For and Since
• Important Rules to Follow When Using For and Since
• Common Mistakes When Using For and Since
• Examples of For and Since

What Is the Difference Between For and Since

The prepositions for and since are used to describe time. However, they are used differently. For shows the duration of an action (how long it lasts), while since shows the starting point of an action (when it began).

For	Since
Used to represent a period of time; it can refer to the past, present, or future.	Used to show a starting point
Followed by a period of time	Followed by a specific point in time
Examples: for 2 hours, for 5 days, for a long time	Examples: since 2 PM, since Monday, since 2020
Answers the question “How long?”	Answers the question “From when?”

Important Rules to Follow When Using For and Since

Understanding a few simple rules can help you use for and since correctly in sentences. Here are some important rules:

Use for with a period of time: Use for when you mention a duration of time.

Example: She has lived here for 10 years.

Use since with a point in time: Use since when you mention a starting point.

Example: She has lived here since 2015.

Use for and since with perfect tenses: For and since are commonly used with present perfect and perfect continuous tenses. Example:

• I have worked here for 3 years.
• I have worked here since 2021.
• Using since to refer to the past until now: Since is used for actions that started in the past and continue to the present. Example: He has been busy since morning.

Common Mistakes When Using For and Since

Even though for and since are simple, learners often confuse their usage. Here are some common mistakes and how to correct them:

Using since for duration

• Incorrect: I have been studying since 2 hours
• Correct: I have been studying for 2 hours

Using for with a starting point

• Incorrect: She has lived here for 2020
• Correct: She has lived here since 2020

Mixing up time expressions

• Incorrect: They have been friends since 5 years
• Correct: They have been friends for 5 years

Incorrect Use with Specific Days or Dates

• Incorrect: He has been absent for Monday
• Correct: He has been absent since Monday

Using Wrong Tense with For and Since

• Incorrect: I am living here since 2020
• Correct: I have been living here since 2020

Examples of For and Since

Here are some simple examples to help you understand how for and since are used in sentences.

Examples using for:

• I have been studying for two hours.
• She has lived here for five years.
• They waited for a long time.
• We have known each other for a decade.
• Examples using since:
• I have been studying here since morning.
• She has lived here since 2018.
• They have been friends since childhood.
• We have known each other since school days.