The amount of residual sugar (RS) in wine can be reported either in grams per liter (g/L) or as a percentage (%). They are just two ways of specifying the same sugar concentration. But, how are the two measures related? Well, it’s actually quite simple to do the conversion.

When a wine’s residual sugar is reported in grams per liter, it specifies the grams of sugar in 100 mL of wine. This is so because a percentage is expressed per hundred. So, to briefly get a bit mathematical, since 1 liter is 1,000 milliliters, if you have a wine with a given number of grams per liter of residual sugar, you have to divide that number by 10 to to get the value per 100 milliliters so that it can be expressed as a percentage.

Simply put:

To convert grams per liter to a percentage: % sugar = grams per liter divided by 10
- % Sugar = g/L ÷ 10
To convert a percentage to grams per liter: Grams/L = Percentage x 10
- g/L = % x 10

So, a wine 5 g/L of residual sugar is 0.5% sugar (5 ÷ 10) and a wine that has 2% residual sugar has 20 g/L (2 x 10 = 20 g/L)

Here are some typical amounts of residual sugar in typical wines: