Christmas Lights Calculator
Planning your holiday decorations? This calculator helps you estimate how many Christmas lights you need for either a tree (based on height) or an outline (house perimeter, railings, etc.). Using standard spacing guidelines - approximately 100 lights per 30 cm for a full tree look, or your specified bulb spacing for outlines - you'll know exactly how many strands to buy. Adjust the density factor for sparser or more luxurious coverage.
How We Calculate This
Tree mode: bulbs = (height ÷ 0.30) × 100 × density factor (based on 100 lights per 30 cm of tree height). Outline mode: bulbs = (length ÷ bulb spacing) × density factor. String length equals bulbs × spacing.
Frequently Asked Questions
How many lights per foot of tree?
A common rule is about 100 lights per vertical foot for a "full" look on a tree, which accounts for wrapping around branches at multiple levels. For a sparser look, use 50-75 lights per foot.
What is the density factor?
The density factor multiplies your light count. Use 1.0 for standard coverage, 1.5 for extra twinkle, or 0.5 for a minimalist look. Higher values mean more lights.
How many lights for a house outline?
For outlining a house, measure the total perimeter you want to decorate (roofline, windows, doors). At 10 cm spacing, you'll need about 10 lights per meter.
LED vs incandescent - does it matter for count?
The number of bulbs doesn't change, but LEDs are safer for dense coverage since they run cooler. LEDs also use about 90% less energy, so you can add more without overloading circuits.
Related Calculators
You might also find these calculators helpful: Electricity Cost Calculator, and Length Converter.
Light counts are estimates for decorative guidance. Actual needs vary based on tree shape, desired density, and personal preference. Always follow electrical safety guidelines and don't overload circuits.