It depends some on the method of extracting the oil, but around 14kg of seeds, maybe a bit less, to get 1 litre of oil, more or less. That's a lot of seed for so little oil, but then the seeds aren't really that big after you take off the hull and...
thats like asking how many olives it takes to make a quart of oil or how many grapes it takes to make a glass of juice or wine.there is no formula to calculate.i would say that an average sunflower would make a teaspoon of oil but the flowers are so many sizes and the smaller one is the less seeds it produces.
In the food industry, sunflower oil is also used to make fried fast food, such as potato chips and corn chips. The sunflower oil cake which obtained after squeezing contains 30%~36% of protein and 8%~11% of fat. In addition to feed, oil cake can also be used to produce monosodium glutamate and soy sauce.
Making your own sunflower oil can have multiple purposes, whether for cooking or adding to homemade beauty products. If you choose to use the large, confectionary sunflower seeds, you will need additional equipment and a press in order to grade, dehull, and winnow the seeds.
The oil must be extracted to separate it from the solids using one of several processes. Three types of sunflower oil produced for cooking applications, which vary in oleic levels, are: NuSun, linoleic and high oleic. Oil-seed-type sunflower seeds are used for oil production rather than for common snack seeds.
Vegetable oils are also used to make biodiesel, which can be used like conventional diesel.Some vegetable oil blends are used in unmodified vehicles but straight vegetable oil, also known as pure plant oil, needs specially prepared vehicles which have a method of heating the oil to reduce its viscosity.
Oil Content can be an important factor when choosing a sunflower hybrid depending on which market the sunflowers are being sold into. The oil crush market wants a higher oil content, but a hybrid being sold into the dehull market is less concerned. Test Weight in sunflowers
Sunflower oil can be extracted using chemical solvents (e.g., hexane), or expeller pressing (i.e., squeezed directly from sunflower seeds by crushing them). "Cold-pressing" (or expeller pressing) sunflower seeds under low-temperature conditions is a method that does not use chemical solvents to derive sunflower seed oil. 
Sunflower Seeds Health Benefits . Sunflower seeds are obtained from the sunflower plant and are black or grey in color. They are found inside black shells and have to be extracted and ground to obtain oil from these seeds. The following are the health benefits of sunflower seeds: Good Diet Source for Rare Mineral Salts
From 2007 to 2015, the most notable growth rates of sunflower-seed and safflower oil production among the main producing countries was attained by Ukraine (+X% per year), while the other global leaders experienced more modest paces of growth. Top X Sunflower-Seed And Safflower Oil Producing Countries in the World