How do you measure Christmas lights for a house?

Decorating your house with Christmas lights is a fun holiday tradition that can really make your home stand out. But before you start stringing up lights, it’s important to measure your house and calculate how many lights you’ll need. Proper measurements ensure you buy enough lights to decorate your entire house. It also helps you space out the lights evenly for the best visual impact.

Why measure your house for Christmas lights?

There are a few key reasons you should measure your house before buying Christmas lights:

  • Determine how many lights you need – Measuring first allows you to calculate the total length of lights required. This way you can buy the right amount of lights for your decorating project.
  • Space lights evenly – With measurements, you can space out light strands evenly around windows, doors, roof lines, etc. Even lighting looks more professional.
  • Stay within your budget – Knowing the length needed allows you to budget accordingly and avoid buying too many or too few lights.
  • Save time – You’ll minimize time-consuming adjustments later if you measure first and have the right amount of lights.
  • Be safe – Measurements ensure you don’t overload electrical circuits or create tripping hazards with wires.

How to measure your house for Christmas lights

Follow these steps to measure your house and determine how many lights you’ll need:

Make a list

Walk around your house and make a list of all the areas you want to decorate with Christmas lights. This may include:

  • Roofline
  • Windows
  • Doors
  • Under roof eaves
  • Porch railings
  • Columns
  • Landscaping
  • Trees/bushes

Having a list helps you measure everything systematically and not miss any spaces.

Measure lengths and widths

Now it’s time to measure. For each decorating area, measure the length across and height/width. This gives you the total square footage of lights needed per area. Measurements to take include:

  • Roofline – Measure the length and height of your roofline completely around the house.
  • Windows/doors – Measure around the outer edges of each window and door frame.
  • Eaves – Determine the length and depth of the underside area of your roof overhangs.
  • Railings/columns – Measure the height and width of porch railings and decorative columns.
  • Landscaping – Measure around the perimeter of any bushes, trees, or areas you want to decorate outside.

Make sure your measurements are precise. Round up to the nearest whole number. Having accurate measurements will ensure you know exactly how many lights are required.

Factor in spacing

In addition to the basic length and width of decorating areas, you’ll need to account for proper light spacing:

  • On a roofline, you’ll need to leave 2-3 inches between each light strand.
  • For wrapping columns or railings, allow 1-2 inches between strands.
  • In bushes and landscaping, you can place strands closer together, about 1 inch apart.

Factor in this spacing as you calculate your total lighting needs for each area. Proper spacing creates an even, cohesive look.

Calculate total light length

Use your measurements to calculate the total length of Christmas lights needed:

  • Multiply length x width of each decorating area to get square footage.
  • Divide square footage by spacing guidelines for that area.
  • Add up the light lengths needed for all decorating areas.

This gives you the total length of Christmas lights required to decorate your entire house. Order enough light strands to meet or slightly exceed this length.

Tips for measuring Christmas lights

Follow these tips for more accurate measurements and the best results:

  • Use a steel measuring tape for precision. Laser measurement tools also work well.
  • For roof measurements, use a ladder to reach the peak safely.
  • Have an assistant help hold the tape measure for very long lengths.
  • Take measurements in the daytime for good visibility.
  • Round up measurements to the next foot or inch.
  • Add about 10% extra lights to allow for mistakes or breakage.
  • Take photos as you measure for reference later when decorating.

How many lights do you need per foot?

A standard mini Christmas light strand is about 16 to 20 feet long with 50 bulbs. That equals approximately 3 lights per foot.

So when calculating:

  • 100 feet of lights needed = About 33 strands
  • 200 feet = About 67 strands
  • 300 feet = About 100 strands

Determine your total light length needed, then divide by 16-20 to calculate the number of strands required. Remember to round up. It’s better to have a few extra strands than to run short.

Choosing the right Christmas lights

With your measurements complete, now you can shop for the perfect Christmas lights! Here are some popular options:

Mini lights

Mini lights are the smallest and most versatile:

  • Come in strands of 50, 100 or 150 lights
  • Bulbs are under .25″ diameter
  • Ideal for decorating roof lines, railings, bushes, and wrapping trees
  • Create a uniform look with dense, even lighting

C7 lights

C7 bulbs are larger, transparent bulbs on screw bases:

  • Come in strands of 25 lights
  • Bulbs are .5″ diameter
  • Great for outlining windows, doors, and roof lines
  • Provide a retro, classic look

C9 lights

C9 Christmas lights have the largest bulbs:

  • Come in strands of 25 lights
  • Bulbs are .75″ diameter
  • Often used for bold accent lighting
  • Make a dramatic statement on columns, eaves, or landscaping

LED vs. incandescent lights

You’ll also need to choose between LED and incandescent bulbs:

  • LED – More expensive initially but use 80% less energy and last 5-10 times longer. Ideal for hard to reach areas.
  • Incandescent – Traditional Christmas light, produces a warm glow. Budget friendly option but don’t last as long.

Plan your display based on your goals, space, and budget. Mixing different bulb sizes and styles creates visual interest.

Calculating Christmas lights for common decorating spaces

To give you an idea of how light measurements work, here are some examples for typical house spaces:

Porch railings

Your front porch has two railings that are each 6 feet long and 2 feet high. Leave 1 inch between light strands.

  • Railings = 6 x 2 = 12 sq ft each
  • Two railings = 24 sq ft total
  • Spacing of 1 inch = 24 strands needed
  • With 16 foot strands, you’ll need about 2 bundles of lights


You want to outline 8 windows that are each 3 feet wide x 5 feet high. Allow 2 inches between strands.

  • Each window = 3 x 5 = 15 sq ft
  • 8 windows = 15 x 8 = 120 sq ft
  • Spacing of 2 inches = 60 feet of lights needed
  • 60 feet divided by 16 feet per strand = About 4 strands needed


Your ranch style house is 50 feet across the front and 30 feet deep. The roof height averages 12 feet. Leave 3 inch spacing.

  • Front = 50 x 12 = 600 sq ft
  • Sides = 30 x 12 x 2 = 720 sq ft
  • Total = 1,320 sq ft
  • Spacing of 3 inches = 440 feet
  • With 100 foot strands, you’ll need about 5 strands

Tree wrapping

You want to wrap a 5 foot diameter evergreen tree from top to bottom. Use 1 inch spacing.

  • Tree height = 12 feet
  • Tree circumference = Pi x D = 3.14 x 5′ = 15.7 feet
  • Total length = 12 x 15.7 feet = 188 feet
  • Spacing of 1 inch = About 188 strands needed

Wrap trees tightly for the full effect. For larger trees, you may need to wrap garland-style vertically.

Creating a lighting plan

Once you’ve calculated your lighting needs, draw out a lighting plan for your house. This should include:

  • Lighting areas, measurements, and number of strands needed
  • Where you’ll plug in and connect light strands
  • Safety notes like keeping wires away from water sources
  • Lighting order plan – which areas to light first

Having a lighting plan makes the decorating process go smoothly and efficiently.

Safety tips for Christmas lights

When decorating your home with Christmas lights, be sure to make safety a top priority:

  • Use a GFCI outlet near water sources like bushes
  • Check for damaged cords and discard loose, frayed strands
  • Do not overload electrical circuits
  • Keep extension cords out of walkways to avoid tripping
  • Never remove the grounding pin from a 3-prong plug
  • Don’t nail, staple or damage light strands
  • Turn off all lights when leaving home or sleeping
  • Use a sturdy ladder and have someone stabilize it when decorating rooflines
  • Follow all manufacturing instructions carefully

Proper measurements and planning will also help you safely decorate without overloading any area. With some preparation and common sense, you can easily prevent hazards.

Hiring a professional

If measuring and decorating your entire house with Christmas lights seems overwhelming, consider hiring a professional lighting company.

Pros can help in several ways:

  • Perform all measurements to determine your lighting needs
  • Provide a computer visualization of your decorated home
  • Install and test all lights to ensure they work properly
  • Decorate hard to reach areas like roofs safely
  • Take down and store your lights after the season

Hiring a professional takes the hassle out of decorating while giving your home a picture perfect look. Just provide a budget and let them handle the details!


Measuring your house for Christmas lights takes a bit of time and effort up front. But the payoff is getting to decorate your entire home exactly as desired. Accurate measurements ensure you have the perfect amount of lights spaced optimally for a pro-level look.

Follow the steps to measure each decorating area, factor in proper spacing, and calculate your total light strand needs. Shopping with a lighting plan and measurements in hand makes selecting lights easy. Have fun decorating your home with beautiful Christmas lights that make the holidays bright!

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