The cheaper approved weighing machines are calibrated ("adjusted") by Trading Standards for use at one location (sometimes a town, usually one postcode), this is to allow for variations in gravity. The country is divided into 'gravity zones', each of these zones has a number, the number (and the town / postcode) is printed on the certificate that comes with the machine.

In this article I will tell you how to find out the gravity number for your town. Then you will know if it is approved for use in another town (e.g. if you move or if you travel around the country). THIS DOES NOT APPLY TO ALL APPROVED WEIGHING MACHINES! - there are more expensive weighing machines that can be used anywhere, e.g. Ohaus, or this A&D model:



We sometimes have secondhand approved weighing machines or sale.


Each approved EW-150i-EC weighing machine is calibrated (set up) by a Trading Standards technician for use in one location. If you use the machine (as an approved machine - for buying precious metals) in another town, that is OK providing the 'gravity number' is the same. If you are not using it as an approved machine (for buying precious metals) there are no regulations, there is no need to read any further.

Below are instructions telling you how to find the 'gravity number' for any town.
This is useful if:
- you already have an approved balance and you are moving, and you want to know if it will still be approved for the new location
- you travel around the country and want to know the locations at which you can use the machine
- you are buying a secondhand balance and you want to know if you can use it (for buying precious metals) in your town

Go to the gravity zone calculator and follow these instructions:

On the panel on the left click the tab Gravity

Then in the middle of the panel click the tab click the tab City Search

Enter Name or first letters of city * (you don’t have to enter the country)


If there's more than one town of that name, you will see list, click on the one marked "(United Kingdom)"

The gravity zone is the number in red by the word GRAVITY, it will be to four decimal places but you only need to know it to three decimal places

* If your town isn't listed, enter the name of the nearest larger town. If you don't know where the 'nearest larger town' is (e.g. you are in another part of the country at the head office of a large company), look at any map, I recommend