The amount of Christmas lights needed for a 7ft Christmas tree will depend on the style of lights you are using and how you are planning to decorate the tree. However, as a general rule of thumb, it is recommended to use approximately 300-400 lights per foot of tree height. This means you will need approximately 2100-2800 lights for a 7ft tree. Remember to consider the type of lights you are using and the desired effect you want to create when deciding how many lights to use.