There are two basic units: the kilogram (or kilo) and the litre. Each divides into a 1 000, so there are 1 000 grams (g) in a kilogram and 1 000 millilitres (ml) in a litre. (kilo- means 1 000 and milli- means 1/1 000).

Useful ballpark measures to learn are 100 / 250 / 500 / 750 in either g or ml.

Linear measures

These are used for cake tins, thicknesses, lengths and so forth. In cooking these will be either centimetres (cm) or millimetres (mm), that is, either a hundredth of a metre or the smaller thousandth of a metre. All rulers carry cm or mm.

Oven temperatures

These have been in degrees Celsius for more than 30 years. Very few ovens remain in Fahrenheit. If you have a gas oven then you do not need to follow a temperature scale. Sugar and deep-frying thermometers all have °C on them.

Cake tins and bowel sizes

These will be expressed in cm (for length or diameter) or ml or litre (for volume) or kg (weight): "use a 20 cm cake tin", "roll pastry to a 5 mm thickness", "spoon into a 1 litre soufflé dish", "turn into a 1 kg loaf tin", just as we used to talk about inches, pints and pounds.

Spoons and cups

Although there are metric measuring spoons in 5 ml / 10 ml / 15 ml sizes, metric cooks refer to them by their everyday names - teaspoons/dessertspoons/tablespoons - even in countries that have been metric for over a hundred years. A metric cup (used in Australia) is 250 ml, a quarter of a litre. Cups are not a standard UK measure. The US cup is the equivalent of 237 ml, an awkward size in UK recipes.

Following a metric recipe

More and more UK magazines, books and TV chefs are using metric only measures without converting. So have a go and choose a simple recipe to practice on. Free supermarket recipe cards are great examples of easy recipes, especially those from Sainsbury's and Waitrose! Get out your scales, jugs and rulers and choose a simple recipe that is in metric only (so there is no temptation to peek at imperial!)

If you have a much loved recipe in imperial there is no need to convert it. Just carry on as before. You may have some left-over ingredients because butter, flour, sugar etc. are sold in metric units. However, many old recipes can be easily adapted to metric - just keep the proportions the same. See the metric conversion chart from the Guild of Food Writers.

Buying fresh produce in metric

By law all UK scales must show metric measures, so if you are following a casserole or roasting recipe that calls for a weight in kilograms or grams, just ask the butcher, fishmonger or greengrocer for the metric weight. It will be easy for him or her to weigh it out. To get used to the metric weight of your fresh produce, next time you shop for your usual joint size or meat measured in lbs, ask "What's that in metric?" Most shopkeepers are only too happy to be helpful. And like all good shopkeepers they will say "little bit over - is that OK?"

Working out how much to buy