by Mike Wright » Sat Jan 21, 2006 7:29 pm
Litres are a measure of volume (like pints), whereas tonnes are a measure of mass, also often wrongly referred to as weight. So it depends on the density of the substance. If it is water it is easy - 1 litre = 1 kg, so 1000 litres = 1000kg = 1 tonne. A tonne is 1000kg. If you know the density of your substance relative to water you can convert from there. For example if density is 1/2 that of water 1000 litres = 500kg = 0.5 tonnes.