Maple syrup is about 60% as sweet as granulated sugar but, because it is more flavorful, most sources recommend using 3/4 cup of maple syrup for every cup of sugar in the original recipe. The exception seems to be for baking muffins, where a 1 to 1 substitution may be more appropriate.

For every cup of maple syrup, reduce the main liquid ingredient (as opposed to oil or eggs that the recipe calls for) by about 3 tablespoons.

Most sources also suggest reducing the baking temperature by 25 degrees because syrup will caramelize and burn more easily than white sugar.