How many lights per foot of tree

The Omni Calculator computes how many lights to put on Christmas trees.

How many lights should go on a Christmas tree?

This question gets asked so often during the holidays that everyone from retailers like Lowe’s to publications like Real Simple and Better Homes & Gardens have tried to answer it.

“A good rule of thumb is 100 lights for every foot-and-a-half of tree,” according to Lowe’s. But Better Homes & Gardens recommends using three 100-light sets for every foot of a tree’s height. And Real Simple suggests 100 lights for every foot.

Since there’s no consensus about just how many lights is right, trimming a tree can be daunting for novice decorators. It’s even given headaches to mathematicians like Troy Henderson, a professor at the University of Mobile’s College of Arts and Sciences in Alabama. Last year, he developed what he describes as a hack to perfectly light a Christmas tree. By thinking of a holiday evergreen as an inverted cone, Henderson used the mathematical concept known as the conical helix to determine the right number of lights for his tree. He explained:

“Our Christmas tree is 3½ feet wide at its base and 8 feet tall. When using 75 feet of lights, the vertical spacing between rotations is about 7 inches. This ensures that if we begin wrapping the lights in a conical helix pattern beginning at the bottom of the tree and vertically space the lights by about 7 inches between successive rotations, the strands of lights will terminate precisely at the top of the tree.”

Henderson has made his Christmas tree light-spacing formula available to the public, and Dominik Czernia and Álvaro Díez, physics doctoral candidates studying in Poland and Turkey, respectively, have expanded on the mathematician’s work. They feature their approach on a web tool called the Omni Calculator. The free calculator factors in tree lights and ornaments and provides users with step-by-step computation and visualization. To use it, you’ll need to know some basic information, such as your tree’s height and bottom diameter, the length and spacing of the light strands, and the diameter of the ornaments you plan to use.

So who’s most likely to use a Christmas tree calculator? Is it designed for the math-and-science crowd or for anyone who wants a perfectly decorated tree? I interviewed Czernia and Omni Calculator Project founder Mateusz Mucha about the tool.

The Omni Calculator can help you figure out how many lights your Christmas tree needs.Omni Calculator
Nadra Nittle

Who knew that decorating a Christmas tree even stumps physicists? What prompted you all to develop a web tool that could simplify this process for everyone?

Dominik Czernia

We had been wondering how many lights and ornaments make a Christmas tree so beautiful. To our surprise, it was impossible for us to make at least some rough estimations. With the help of Dr. Henderson’s formula, we developed our intuitive tool with visualization of your perfect tree with lights and baubles. The best thing about it is the simplicity — all you need to enter are your tree’s dimensions.

Nadra Nittle

The conical helix is the key to the calculator. Can you describe how this pattern works in more detail?

Dominik Czernia

We surely can all agree that when we look at the Christmas tree, its shape reminds us of a cone, a pyramid with a circular base. So what does the conical helix have in common with a cone? Imagine you’ve got a ribbon that you attach to the top of a cone. Then start wrapping it around the cone, moving downwards until you reach the base. The curve formed by the ribbon is a conical helix.

Nadra Nittle

Using the conical helix pattern, it’s helpful to look at a Christmas tree from the top while decorating it. Why is that?

Dominik Czernia

One of the aesthetic factors that please most people is uniformity. The best way to check it is to look at a Christmas tree from the top so you can see every single ornament on it. Do they look uniformly distributed from that point of view? Perfect! That’s what we’re aiming for. This is another unique feature of a conical helix; it gives us excellent uniformity.

Nadra Nittle

An efficiently decorated tree might even help cut down on electricity costs. That’s amazing.

Dominik Czernia

It surely could help. The larger number of lights naturally translates into higher power consumption. However, we don’t want to resign from the lights entirely; they’re one of those things which bring a magical Christmas atmosphere. What we can do, though, is plan in advance how bright our Christmas tree should be to buy light strands of appropriate length.

This allows us to avoid the situation in which the light strand is too long, and we hide it somewhere in the tree foliage or leave it trailing on the floor. But still, these redundant lights will use electricity and generate costs! A well-decorated tree has uniformly distributed lights around; thus, it looks as pretty as we wanted, and simultaneously, the length of strands is perfectly adjusted to the Christmas tree’s dimensions.

Nadra Nittle

Who’s the target audience for the Omni Calculator? Is it mostly math-and-science types, or have normies expressed interest?

Mateusz Mucha

Omni Calculator is used both by geeks and people who aren’t as confident with math, but it’s actually the latter group we think about the most. People have thousands of decisions to make that they should base on numbers. But they don’t think in terms of math formulas, don’t have the time, or just don’t feel like making this effort. And they end up making bad decisions. It’s our goal to make this process easy, fast, and kind of fun so that people are more likely to do the math.

Nadra Nittle

On the Omni Calculator site, there’s a funny gif of Monica from Friends. She turns a Christmas tree around to show off her expertly decorated side of the tree and to hide the very messy side her friends decorated. Do you think Monica would use your calculator?

Mateusz Mucha

Sure, but it’s actually Joey and Rachel who could get the most value out of it. Chandler suffers through Excel every day, so he’d be capable. Ross would somehow make the tree about dinosaurs, and Phoebe would try to save the tree and homeless squirrels instead.

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How Many Christmas Lights You Need to Decorate Your Home


Lee Wallender

Lee Wallender

Lee has over two decades of hands-on experience remodeling, fixing, and improving homes, and has been providing home improvement advice for over 13 years.

Learn more about The Spruce's Editorial Process

Published on 12/10/21

Fact checked by

Sarah Scott

Fact checked by Sarah Scott

Sarah Scott is a fact-checker and researcher who has worked in the custom home building industry in sales, marketing, and design.

Learn more about The Spruce's Editorial Process

ArtBoyMD / Getty Images

Christmas lights add sparkle, color, and shine to the holiday season. Yet estimating the number of Christmas lights you need to decorate your home can be difficult. House eaves, columns, peaks, windows, and other architectural features are too large to easily calculate. But there are a few rules-of-thumb and guidelines that help you buy the right number of lights to avoid blank spots or overloading the home with too many lights.

Number of Christmas Lights for Most Houses

If you want Christmas lights on your home displayed in that classic manner—on the eaves' fascia—purchase the following.

For Front Only

Use two strands of 32-foot mini lights, for a total of 200 lights, for either an average- or small-sized house.

If you prefer the larger-bulb C9 lights in 16-foot lengths, double the number of strands. So, you would use four strands of C9s, for a total of 100 lights.

The C9 strands come with a quarter to half as many bulbs as the mini lights, depending on length. Though fewer in number, C9 bulbs are far brighter than mini lights.

What Are Eaves and Fascia?

Eaves are roof projections that overhang the exterior siding. The fascia is the vertical part of the eaves that is most commonly used for attaching Christmas lights.

For Front and Two Sides

  • Average House: Use four strands of 32-foot mini lights, plus two strands of 14-foot mini lights, for a total of 500 lights. For C9 bulbs, you can use 10 of the 16-foot-long strands.
  • Small House: Use four strands of 32-foot mini lights, for a total of 400 lights. For C9 bulbs, use 7 of the 16-foot-long strands.

Large Projections

If the front or sides have large architectural details like awnings, cupolas, and gables add another 10 feet per detail.


An average-sized, newly constructed house is about 2,300 square feet. A small house is approximately half that: 1,200 square feet. For both houses, the length of the front is calculated at 50 linear feet. For the small house, each side is assumed to be 24 linear feet. For the average-sized house, each side is assumed to be 46 linear feet.

Popular Christmas Lights and Coverage

Type (Single Strand) Average Length or Area Number of Lights
Mini strand lights 14 feet 50
Mini strand lights 32 feet 100
Mini icicle lights 26 feet 300
Large C9 style bulbs 16 feet 25
Mid-size C7 style bulbs 24 feet 25
Small C3 style bulbs 18 feet 50
Net lights 4-foot by 6-foot 150
Net lights 2-foot by 8-foot 150

How to Calculate How Many Christmas Lights You Need

Calculate the number of Christmas lights needed to decorate your home by first measuring your home, then adding outdoor features.

  1. Measure the length of the front of your house (that is, the width of the house if you are looking at it from the street). Use a laser measuring tool or a tape measure.
  2. If you want to cover the left and right sides, measure those, too. The back section of homes is typically not covered, but you may decide to do this to add holiday cheer to your deck, patio, or backyard.
  3. If you want to cover the upper portion of triangle-shaped roof peaks (4:12 pitch ratio), this length will be 26 1/2 feet for each peak. This is based on a house that is 25 feet long on the side.
  4. Select the number of outdoor features desired and add them together.
  5. Add a foot or two to all of the strand (not net) light measurements. Christmas light length is expressed in two numbers: strand length and lighted length. The lighted length is always about a foot less than the strand length.

Number of Lights Needed for Outdoor Features

  • Bushes and Hedges: One to two 4-foot by 6-foot light nets per bush or hedge.
  • Trees: One 32-foot strand (100 lights) for every 1 1/2 vertical feet of an evergreen tree; or, about 500 to 600 lights for an 8-foot tree.
  • Windows: One 16-foot strand per single-width window.
  • Doors: One 16-foot strand per door.
  • Window Boxes: One 14-foot strand of 50 lights per window box.
  • Columns and Pillars: One 32-foot strand of 100 lights per 7 vertical feet of column or pillar.
  • Deck Railings: Measure the deck railing and use that measurement to determine how long the lights should be. If you plan to wrap the lights rather than use clips, you will lose about 1 foot. So, add an extra foot.


Do you want tighter light spacing? One easy way to do this is to double the lights back. Adjust the second run so that its bulbs fall between those of the first run. Just make sure that your outdoor GFCI outlet and circuit can handle the increased load.

Number of Lights for a Christmas Tree

Underestimating the number of lights on the Christmas tree results in a dark, drab tree. Too many lights overloads the tree and detracts from ornaments and the tree itself.

The easy rule of thumb is to use one strand of lights (100 lights) for each vertical foot of the Christmas tree. If you like a slightly brighter tree, you don't need much more: Just add one more strand.

Tree Height Average Number of Strands Strands for a Brighter Tree
4 feet 4 strands or 400 lights 5 strands or 500 lights
5 feet 5 strands or 500 lights 6 strands or 600 lights
6 feet 6 strands or 600 lights 7 strands or 700 lights
7 feet 7 strands or 700 lights 8 strands or 800 lights
8 feet 8 strands or 800 lights 9 strands or 900 lights

The 7 Best Outdoor Christmas Lights, Tested By the Spruce

Article Sources

The Spruce uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

  1. Characteristics of New Housing. United States Census Bureau.

  2. “Deck the Halls” Safely: CPSC Estimates More Than 15,000 Holiday Decorating Injuries During November and December. United States Consumer Product Safety Commission.

Classification of wind force, sea waves and visibility - What is the Classification of wind force, sea waves and visibility?

IA Neftegaz.RU. Classification of wind force, sea waves and visibility.

Beaufort scale

0 points - calm
A mirror-smooth sea, almost motionless. Waves practically do not run up to the shore. The water is more like a quiet backwater of a lake than a sea coast. Haze may be observed above the surface of the water. The edge of the sea merges with the sky so that the border is not visible. Wind speed 0-0.2 km/h.

1 point - quiet
Light ripples on the sea. The height of the waves reaches up to 0.1 meters. The sea can still merge with the sky. There is a light, almost imperceptible breeze.

2 points - light
Small waves, no more than 0.3 meters high. The wind speed is 1.6-3.3 m/s, you can feel it with your face. With such a wind, the weather vane begins to move.

3 points - weak
Wind speed 3.4-5.4 m/s. Slight roughness on the water, occasionally lambs appear. The average wave height is up to 0.6 meters. A weak surf is clearly visible. The weather vane spins without frequent stops, the leaves on the trees, flags and so on sway.

4 points - moderate
Wind - 5.5 - 7.9 m / s - raises dust and small pieces of paper. The weather vane spins continuously, the thin branches of the trees bend. The sea is restless, in many places lambs are visible. Wave height up to 1.5 meters.

5 points - fresh
Almost the entire sea is covered with white lambs. Wind speed 8 - 10.7 m/s, wave height 2 meters. Branches and thin tree trunks sway.

6 points - strong
The sea in many places is covered with white ridges. The height of the waves reaches 4 x meters, the average height is 3 meters. Wind speed 10.8 - 13.8 m/s. Thin tree trunks bend, and thick branches of trees, telephone wires buzz.

7 points - strong
The sea is covered with white foamy ridges, which are blown off the surface of the water from time to time by the wind. The wave height reaches 5.5 meters, the average height is 4.7 meters. Wind speed 13.9- 17.1 m/s. Medium tree trunks sway, branches bend.

8 points - very strong
Strong waves, foam on each crest. The height of the waves reaches 7.5 meters, the average height is 5.5 meters. Wind speed 17.2 - 20 m/s. It is difficult to go against the wind, it is almost impossible to talk. Thin branches of trees break.

9 points - storm
High waves on the sea, reaching 10 meters; average height 7 meters. Wind speed 20.8 - 24.4 m/s. Large trees bend, medium branches break. The wind rips off poorly reinforced roof coverings.

10 points - strong storm
The sea is white. Waves crash on the shore or on the rocks with a roar. The maximum wave height is 12 meters, the average height is 9 meters. The wind, at a speed of 24.5 - 28.4 m/s, rips off roofs, significant damage to buildings.

11 points - severe storm
High waves reach 16 meters, with an average height of 11.5 meters. Wind speed 28.5 - 32.6 m/s. Accompanied by great destruction on land.

12 points - hurricane
Wind speed 32.6 m/s. Serious damage to capital buildings. The wave height is over 16 meters.


A tropical storm is named when its accompanying wind reaches 62 km/h.
According to the Saffir-Simpson scale, which assesses potential damage from the elements, a hurricane is assigned a category:

  • 1 and category - wind speed - more than 120 km/h.
  • 2 i - more than 150 km/h,
  • 3 i - 180 km/h;
  • 4 i - at 210 km/h;
  • 5 i - the most dangerous category - with wind speeds over 250 km/h.

Sea wave scale

In contrast to the generally accepted twelve-point system for estimating wind, there are several estimates of sea waves.
British, American and Russian grading systems are generally accepted.
All scales are based on a parameter that determines the average height of significant waves.
This setting is called Significance Wave Height (SWH).
In the American scale, 30% of significant waves are taken, in the British 10%, in the Russian 3%.
Wave height is measured from the crest (the top of the wave) to the trough (the base of the trough).

Below is a description of the wave height:

  • 0 points - calm,
  • 1 point - ripples (SWH < 0.1 m),
  • 2 points - weak waves (SWH 0.1 - 0.5 m),
  • 3 points - light sea (SWH 0.5 - 1.25 m),
  • 4 points - moderate waves (SWH 1.25 - 2.5 m),
  • 5 points - rough sea (SWH 2.5 - 4.0 m),
  • 6 points - very rough sea (SWH 4.0 - 6.0 m),
  • 7 points - strong excitement (SWH 6.0 - 9.0 m),
  • 8 points - very strong sea (SWH 9.0 - 14.0 m),
  • 9 points - phenomenal sea (SWH > 14.0 m).

In this scale, the word "storm" is not applicable.

Since it is not determined by the strength of the storm, but by the height of the wave.

Storm is defined by Beaufort.

For the WH parameter for all scales, it is precisely a part of the waves (30%, 10%, 3%) that is taken because the magnitude of the waves is not the same.

At a certain time interval there are waves, for example, 9 meters, as well as 5, 4, etc.

Therefore, each scale has its own SWH value, where a certain percentage of the highest waves is taken.

There are no instruments for measuring wave height.

Therefore, there is no exact definition of the score.

The definition is conditional.

On the seas, as a rule, the wave height reaches 5-6 meters in height, and up to 80 meters in length.

Visibility scale

Visibility is the maximum distance at which objects are detected during the day and navigation lights at night.

Visibility depends on weather conditions.

In metrology, the influence of weather conditions on visibility is determined by a conditional scale of points.

This scale is a way of indicating the transparency of the atmosphere.

Distinguish between day and night visibility.

Below is the daily range scale:

Up to 1/4 cable
About 46 meters. Very poor visibility. Thick fog or blizzard.

Up to 1 cable
About 185 meters. Bad visibility. Thick fog or sleet.

2-3 cables
370 - 550 meters. Bad visibility. Fog, wet snow.

1/2 mile
About 1 km. Haze, thick haze, snow.

1/2 - 1 mile
1 - 1.85 km. Average visibility. Snow, heavy rain

1 - 2 miles
1.85 - 3.7 km. Haze, mist, rain.

2 - 5 miles
3.7 - 9.5 km. Light haze, haze, light rain.

5 - 11 miles
9.3 - 20 km. Good visibility. Visible horizon.

11 - 27 miles
20 - 50 km. Very good visibility. The horizon is clearly visible.

27 miles
Over 50 km. Exceptional visibility. The horizon is clearly visible, the air is transparent.

how many boards and timber in 1 cube - Articles - Build with us Kosulino

A lumber cube is a common unit of measure for lumber. Almost all wood products: edged lumber, planed lumber, structural lumber, etc. measured in cubes ( cubic meters ). The only exceptions are piece products and moldings. In other words, 1 cube of lumber is a volume equal to 1 meter (1 m) in all three dimensions ( width, thickness and length ):

Fig. 1 - a cube of lumber

For example, take a board 50x100x6000 mm ( 50 mm thick, 100 mm wide and 6000 mm long ), an ordinary 6-meter edged board. And let's try to figure out how many boards will be in 1 cube (1 m 3 ). Based on the fact that all board dimensions are indicated in millimeters (1 mm), they must first be converted to meters (1 m). For those who do not remember how many millimeters are in a meter, we recall that 1 meter (1 m) \u003d 100 centimeters (100 cm) \u003d 1000 millimeters (1000 mm).

Therefore, the solution is:

  • 1 cube (1 m 3 ) / 0.05 (thickness) / 0.1 (width) / 6 (length) = 33 boards in 1 cube (1 m3)

The volume of one board or one beam is calculated as follows:

  • 0.05 (thickness) * 0.1 (width) * 6 (length) \u003d 0.03 cubic meters the volume of one board with cross-sectional dimensions of 50x100x6000 mm.

Now we will try to answer the question “how many boards in a cube” more clearly and easily, find out what a “board cube” is and present to your attention tables for calculating the cubic footage of boards, timber and other lumber.

Below are tables showing how many boards (boards) are in 1 cube and how many beams are in 1 cube:

How many edged boards are in 1 cube

Timber name Board size (mm) How many boards (pieces) in a cube (in 1 cubic meter) Volume of one board in cubic meters (m 3 )
Edged board 25x100x6000 66 0. 015
Edged board 25x150x6000 44 0.022
Edged board 25x200x6000 33 0.3
Edged board 30x100x6000 55 0.018
Edged board 30x150x6000 37 0.027
Edged board 30x200x6000 27 0.036
Edged board 40x100x6000 41 0.024
Edged board 40x150x6000 27 0.036
Edged board 40x200x6000 20 0.048
Edged board 50x100x6000 33 0. 03
Edged board 50x150x6000 22 0.045
Edged board 50x200x6000 16 0.06
Edged board 65x150x6000 17 0.058

How many timber in 1 cube

Timber name Beam size (mm) How many timber (pieces) in a cube (in 1 cubic meter) Volume of one bar in cubic meters (m 3 )
Beam 25x50x3000 266 0.0037
Beam 30x40x3000 277 0.0036
Beam 30x50x3000 222 0. 0045
Beam 40x40x3000 208 0.0048
Beam 50x50x3000 133 0.0075
Beam 50x70x3000 95 0.01
Beam 50x50x6000 66 0.015
Beam 100x100x6000 16 0.06
Beam 100x150x6000 11 0.09
Beam 100x200x6000 8 0.12
Beam 150x100x6000 11 0.09
Beam 150x150x6000 7 0. 135
Beam 150x200x6000 5 0.18
Beam 150x300x6000 3 0.27
Beam 200x200x6000 4 0.24

How many grooved floor boards in 1 cube

Timber name Board size (mm) How many boards (pieces) in a cube (in 1 cubic meter) Volume of one board in cubic meters (m 3 )
Toothed floor board 38x110x6000 39 0.025
Toothed floor board 38x145x6000 30 0.03
Toothed floor board 40x110x600 37 0. 026
Toothed floor board 40x150x6000 27 0.036
Toothed floor board 45x110x6000 33 0.029

How many wooden lining in 1 cube

Timber name Board size (mm) How many boards (pieces) in a cube (in 1 cubic meter) Volume of one board in cubic meters (m 3 )
Wooden lining 17x95x6000 103 0.009
Wooden lining 18x95x6000 97 0.01
Wooden lining 19x115x6000 76 0.013
Wooden lining 19x145x6000 60 0.

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