Goods sold by weight or measure must normally be sold in metric quantities. For example:
- if you sell by weight, you use kilograms and grams instead of pounds and ounces
- if you sell by volume, you use litres instead of pints, or cubic metres instead of cubic feet
- if you sell by length, you use metres instead of feet and inches
You must mark packaged goods with the metric measure. If you want, you can also show the imperial measure as well. But it must not be more prominent than the metric measure.
Restrictions which limited the range of sizes pre-packaged goods could be packed in (with the exception of wines and spirits) have been removed. Aerosol products can also now be packed by weight or volume. Although goods can now be packed in any size, you may continue using traditional standard pack sizes if you wish.
There are only a few exceptions to the metric unit rules. The following may still be sold by imperial units:
- pints of draught beer and cider
- pints of milk in returnable containers
- troy ounces of precious metals
Northern Ireland Trading Standards officers can advise you. They also make occasional checks to make sure you're following the rules. If you break the rules you could face a large fine.