Add 2 cups water and 2 cups sugar (or any 1:1 amount) to a saucepan.
Let come to a boil over medium, stirring often.
Once the syrup begins boiling, add lavender and continue boiling for 5-30 minutes. (Taste after 5 minutes for strength and preference).
Strain lavender out and let syrup cool completely before bottling and storing in the refrigerator for up to a month.
Notes
The longer you boil the syrup, the thicker it will be. It's better to add more lavender and boil less time for stronger syrup than to boil for longer than 25-30 minutes.