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TheSchoolRun.com closure date

As we informed you a few months ago, TheSchoolRun has had to make the difficult decision to close due to financial pressures and the company has now ceased trading. We had hoped to keep our content available through a partnership with another educational provider, but this provider has since withdrawn from the agreement.

As a result, we now have to permanently close TheSchoolRun.com. However, to give subscribers time to download any content they’d like to keep, we will keep the website open until 31st July 2025. After this date, the site will be taken down and there will be no further access to any resources. We strongly encourage you to download and save any resources you think you may want to use in the future.

In particular, we suggest downloading:

You should already have received 16 primary school eBooks (worth £108.84) to download and keep. If you haven’t received these, please contact us at [email protected] before 31st July 2025, and we will send them to you.

We are very sorry that there is no way to continue offering access to resources and sincerely apologise for the inconvenience caused.

What is mass?

What is mass?
We explain what mass means, how mass is usually measured and how children are taught to convert from one unit of mass to another.

What is mass?

Sometimes people talk about an object having a 'mass' of 2 kilograms. This is another way to refer to the weight of an object.

SATs questions have been known to trip children up by asking them a question about the 'mass' of an object rather than the 'weight', so it's a good maths vocabulary word to know!

How is mass measured?

Mass or weight is usually measured in grams and kilograms.

Children need to learn that there are 1000g in a kilogram. As they move up primary school, they need to be able to convert from one unit to another, so they would need to know that 1.2 kg is 1200g, or that 900g is 0.9kg.

Sometimes, children will learn about 'the mass' of an object in science.