Knowing the size of your oil tank and its capacity will make future orders much easier to make. The average domestic tank capacity usually ranges between 1000 litres to 1350 litres. Some larger domestic tanks have capacity of up to 2500 litres. All recently manufactured oil tanks must state their approximate maximum capacity (in litres) on the Product Label, which is generally located on the front or side of the tank If you are still unsure of your tank's capacity and want advice, please contact ValueOils.com on 0905 88 90 100 and we will do our best to help.