Put sugar, water, and sliced or chopped strawberries in a saucepan. Boil for 6 minutes on medium-high heat.
Mash strawberries.While cooking, use a wooden spoon or potato masher and mash the strawberries.
Strain strawberry solids and pour syrup into an airtight container.Use a mesh strainer to filter out the strawberry solids and discard. The syrup will keep for up to 2 weeks in an airtight container in the refrigerator.