Wines get their sweetness from residual sugar (RS), which is leftover glucose from grape juice that wasn’t completely fermented into alcohol. However, our sense of taste picks up sweetness in varying levels.
Most still wines fall into the dry category, even though our taste buds might tell us differently. Dry wines range from no residual sugar to 1 gram per 5 oz serving (150ml). Just so you know, most super premium red wine producers rarely have more than 1/3 gram of sugar per glass. A quick method of comparison: a packet of Sugar in the Raw contains 5 grams of sugar and a 5 oz serving of Coca-Cola has 16 grams of sugar.
In general, some whites wines are almost always made in a dry style: Sauvignon Blanc, Pinot Grigio, Spanish Albariños and Austrian Grüner Veltliners, for example. Some wines often fall between dry and off-dry: many New World Chardonnays, Rieslings, Viogniers and Pinot Gris, for example.