Metric and Imperial equivalents
This article is a travel topic Most countries in the world now use the metric system. Almost the only holdouts are the USA and the United Kingdom which, oddly enough, still use the old British Imperial system of weights and measures. The only units the two systems have in common are time units from second to century. We use "=" signs below, but all are approximate. ContentsTemperature
For those who are not used to Metric thermometers, there are a few ways to think about it... Option 1: From Metric (Celsius) to Fahrenheit, double the number and add 30. From Fahrenheit to Celsius, subtract 30 and divide in half. This is not exact and it won't work for much higher or lower temps, but it will be close enough to understand what the temperature is. Option 2: A nice little poem to remember for Celsius... Zero is freezing 10 is not 20 is warm and 30 is hot Option 3: For the mathematically inclined: Fahrenheit=(C*1.8)+32. Celsius=(F32)/1.8 Length and distance
Comparisonsit card is about 0.75 mm (3/4 of a millimetre) thick.
Weight
For China, the jing is almost exactly 500 grams. Surface areaFor small things, one might use square inches or square centimeters. There are about 6.5 cm^{2} to one in^{2}. For floor area of an apartment, there are about 11 square feet to the square meter. For large areas, there are about 2.5 acres to the hectare. VolumeThe standard metric unit of volume is the litre. Many things, however, are measured in ml (millilitres) or equivalently in cc (cubic centimetres). Roughly, a teaspoon is 5 cc and a fluid ounce is 30 cc. In both the US and Imperial systems, 4 quarts = 1 gallon and 2 pints = 1 quart. However, the US units are smaller than Imperial counterparts. A US quart is 32 fuid ounces while Imperial is 40; a liter is in between at 35. A US gallon is 128 ounces or 3.78 litres, while an Imperial gallon is 160 ounces or 4.54 litres. For car and motorcycle engines, displacement might be given in cc or litres or cubic inches. 1000 cc or one litre is 61 cubic inches. Comparisons
Metric prefixes1 mm = 1 / 1000 metres, 1 mg = 1 / 1000 g, 1 mL = 1 / 1000 Litres. 1 cm = 1 / 100 metres. 1 km = 1000 metres, 1 kg = 1000 grams. 
