Kg measures mass

if you want to convert from volume to mass, you need to know the density of the substance (different substances have different densities)

then the formula is

mass = density x volume

for water,

density = 1000 kg per m^3

so if you have 0.7m^3 of water, then it’s

mass = 1000 x 0.7 = 700kg

for gold,

density = 19300 kg per m^3

so if you have 0.7m^3 of gold, then it’s

mass = 19300 x 0.7 = 13510kg

so gold weighs 19.3 times as much as an equal volume of water

here’s a list of the densities of some common substances

http://www.simetric.co.uk/si_materials.htm

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If I am reading your question correctly you can’t. Seven tenths of a cubic meter is a measure of volume while kilograms is a unit of weight. The two do not share any common ground. It would be like trying to convert miles into dollars.

You’re about 107 pounds… are you joking about being overweight??? You’re so thin, and at a perfect weight. Stop being influenced by the anorexic movie stars. They are nasty looking in person