Splenda recommends using a one-to-one ratio of Splenda Granulated to sugar when the amount of sugar is 1 1/4 cups or less, or the amount of flour used in the product is at least two times the amount of sugar/Splenda. However, when using more than 1 1/4 cups of Splenda or the amount of flour used is less than two times the amount sugar/Splenda, replace half of the sugar with Splenda to help preserve the best consistency and baking yield.
Splenda Granulated works best with quick breads and cakes. When you are using baking powder or baking soda as a leavening agent, subbing in Splenda is simple. However, if you are thinking of making yeast bread think again. When sucralose mixes with the yeast it does not have the same rise as it would with sugar - this is because yeast actually ferments the sugar which contributes to the leavening.
Finally, do not confuse white and brown sugars. Splenda Granulated is a substitute for white table sugar. If you are looking to reduce the amount of brown sugar in a recipe, it is best to use a brown sugar blend like Splenda Brown Sugar Blend. It is also difficult to replace all of the brown sugar in a recipe as artificial sweeteners will not provide the same functional properties as brown sugar. If you do use Splenda Brown Sugar Blend as a replacement, remember you only need 1/2 the amount of the Splenda blend as you would need for brown sugar.