Kilo means a thousand
The kilogram is the SI base unit of mass and the gram is a thousandth of it, so grams to kilograms is a three-place decimal shift: 500 g is 0.5 kg, 1,250 g is 1.25 kg. Since 2019 the kilogram has been defined from the Planck constant rather than a metal cylinder in Paris, but the gram-to-kilogram ratio was never in question. The imperial rows use the exact 0.45359237 kg pound.
kilograms = grams ÷ 1,000 | grams = kilograms × 1,000
Common kitchen and label figures
A standard bag of flour or sugar is 1 kg (1,000 g, 2.2 lb); a block of butter is 250 g (0.25 kg, 8.8 oz); a tin of beans is about 400 g. Nutrition labels quote per 100 g, which is 0.1 kg or 3.5 oz — handy for scaling a recipe from a label.