Learners' Questions

2019-06-07 Fill up, fill out or fill in what’s the difference – Learners’ Questions

This week’s question

What’s the difference between ‘fill up’, ‘fill out’ and ‘fill in’? – Ailin maria (YouTube)

Answer this

Which of these verbs is able to replace the other two in certain contexts?

Language points

Phrasal verbs
Fill out
fill in and fill up are phrasal verbs. That’s a verb + a particle (a preposition or an adverb). All three use ‘fill’, which means ‘put something in an empty space’. 

Fill up
Fill up can mean ‘make something become full’.

  • I filled the car up with fuel.
  • There’s plenty of food. Fill yourself up.

Fill out
Fill out
 often means ‘complete a form or document’, usually one where spaces have been provided for you write in.

  • If you want to join the gym, please fill out this form.
  • A person can also fill out. This means they become larger or thicker.
  • After three months at the gym, John had really filled out.

Fill in
Fill in, just like fill up, can mean ‘make something full’. 

  • The council filled in a hole in the road.

Fill in, just like fill out, can mean ‘complete a form or document’.

  • If you want to join the gym, please fill in this form.

Fill in can mean ‘temporarily replace someone who is unable to do their job at that time’. We fill in for someone.

  • Elena is sick today. Could you please fill in for her?

A person can fill somebody in on something. This means ‘tell them information that they are missing or don’t know’. 

  • Elena! You’re back. Let me fill you in on what you missed while you were sick.

The answer

Which of these verbs is able to replace the other two in certain contexts?
Fill in. Fill in, just like fill up, can mean ‘make something full’. Fill in, just like fill out, can mean ‘complete a form or document’.

BBC Learning English

Share
Published by
BBC Learning English

Recent Posts

2025-09-17 Israel committing genocide in Gaza: UN commission – Learning English from the News

The story An investigation by the United Nations, called a 'commission of inquiry', has found…

1 week ago

2025-09-03 Earthquakes hit Afghanistan – Learning English from the News

The story A major aftershock has hit eastern Afghanistan, just days after an earthquake measuring…

1 week ago

2025-08-27 Heatwaves speed up ageing process, study says – Learning English from the News

The story A study in Taiwan has found that peoples' biological age increases when they…

1 week ago

2025-08-20 Ukraine: Presidents discuss end to war – Learning English from the News

The story Ukraine's President Volodymyr Zelensky returned to the White House on Monday to meet…

1 week ago

2025-08-13 Is prostate cancer over-treated? – Learning English from the News

The story The charity Prostate Cancer UK, says that the UK is treating too many…

1 week ago