You’ll need about
How many feet of string lights do I need?
The length of string lights you need depends on how you hang them. To run them around the edge of a deck or patio, you need the perimeter — the distance all the way around. To hang them criss-cross overhead (café style), you multiply how many runs you want by how long each run is. Either way, add a little extra for the natural drape and sag and for reaching the power outlet. This calculator adds a 15% slack allowance and tells you how many light sets to buy.
Includes a 15% allowance for sag, drape and reaching power. Measure your real anchor points if you can — corners, posts and hooks add length. Buy connectable sets so you can chain them to the exact length.
Frequently Asked Questions
How do I plan an overhead criss-cross pattern?
Decide how many strands you want running across the space and how far each one spans between anchor points (posts, walls, hooks). Enter those two numbers and the calculator totals the length, plus sag.
Why add 15% extra length?
String lights droop between anchors, and you need slack to reach the nearest outlet. A 15% buffer keeps you from coming up a few feet short — the most common mistake.
Can I connect several sets together?
Most modern outdoor string lights are end-to-end connectable up to a maximum wattage — check the box. Buying connectable sets lets you chain them to the exact length you calculated.
Are these safe for outdoor use?
Use lights rated for outdoors (look for an IP44 rating or higher and a UL/ETL outdoor listing). See our buying guide for weatherproof picks in the length you need.