Home » LED Strip Lights » How Many Feet Of LED Strip Lights Do I Need For My Room? (Perimeter Calculator)

How Many Feet Of LED Strip Lights Do I Need For My Room? (Perimeter Calculator)

One of the most popular uses for strip lights is to run them around your entire room, usually hidden by coving or crown moulding.

This helps create a stylish light that’s easy to adjust to set the perfect mood. But how long of an LED light strip do you need to buy?

No two rooms are the same, so to determine how many feet of LED strip lights you need:

  1. Measure the perimeter of the room
  2. Make sure you account for any alcoves – you need to measure along every surface
  3. Based on the length of a single strip (often 16ft, 32ft, or 50ft), work out how many strips you need
  4. Cut the LED strip light shorter if necessary.

Let’s get into that in a bit more detail, as I explain:

  • How to measure room perimeter for LED strip lights
  • Choosing the luminosity of your LED strip light setup
  • Whether you can use multiple LED strips
  • What to do if your strip lights are too long

How To Measure Room Perimeter For LED Lights?

Brightness of LED Strip Light

To measure the length of LED strip lights you need, simply measure the perimeter of the room. If the room is rectangular, just measure the length and width once, and double the total.

However, if the room has any alcoves or areas that stick out (perhaps over a fireplace), or if the room is L-shaped or has some other configuration, you’re going to need to measure along the length of every wall.

Keep track of the measurements as you go.

You could use a notepad or your smartphone, although don’t be tempted to add it to a calculator as you go as if you press one wrong button or forget whether you’ve added the current wall to your total, you’d have to start again.

Instead, keep track of each individual measurement so that you can check you’ve not missed any area and double-check your calculations once you’re done.

It might be a good idea to roughly sketch out the room on paper, and then add the measurements to the drawing, so you can track where you’ve measured.

Once you have the total, you’ll know how much distance you need to cover for your LED strips and how long a strip you’ll need to buy.

To make things easier, you can also use my perimeter calculator:


Selecting Luminosity Of The LED Strip Lights For The Room

installation of led strip

A luminosity of 1500 lumens per meter (450 lumens per foot) is a good measurement for most LED strip lights, even if you have coving or crown molding shielding some of the light. It’s better to buy brighter and then dim the lights rather than buying LED strip lights that aren’t bright enough.

If you aren’t sheltering the LED strip lights at all, then it may be that they’re too bright – but if that’s the case, use a dimmer switch or buy strip lights with a dimmer functionality built into the power supply, or that you can dim from a remote control or smartphone.

Good LED lights will tell you how many lumens they offer when you buy them – either on the box or in the online product description.

Basic LED strip lights might not advertise their brightness. For those that don’t, check the density – if they have 60 light emitting diodes per meter then they’ll likely be bright enough, but if they’ve used the ‘standard’ 30 LED bulbs per meter and they’re low quality, the LED strip brightness might not be sufficient.

Often with cheap LED strip lights, the light appears to be a nice bright white, but it’s not very powerful as a light source.

It’s always better to buy LED strip lighting that advertises the light output in lumens, or at least from a brand you can trust to have used good quality LED lights that will give off a bright light.

Can I Connect Multiple Strip Lights If One Is Not Long Enough?

led strip installation

It’s possible to connect multiple LED light strips if one isn’t long enough for your room. But you shouldn’t mix brands, you must buy strips that match voltage, and you may suffer from voltage drop, which can make the LED light strip duller the further it is from the power source.

It’s not quite as simple as just buying LED lighting strips that are long enough to completely fill your room.

Firstly, rooms really aren’t a standard size, so LED strip lights can’t be either. So you’d have to be extremely lucky to own a room that perfectly fits the length of an LED strip.

There are some long LED strips (Amazon) available, but often you’ll find that your options are shorter than what you need.

But instead of having to find multiple power outlets, you can connect multiple strips together instead, and power them from one plug.

If you’re planning on connecting multiple light strips, it is always best to buy from the same manufacturer and, ideally, the same product.

Light strips always have a slightly different manufacturing process depending on who makes them.

LED strip lights from one manufacturer might not be compatible with another light strip.

Even if you can physically connect them, they might not be rated for the same power draw, which could mean they’re too dull, or they’re actually overpowered and become dangerous.

Definitely don’t try to connect RGB strips with white strips, or even cool white and warm white strips. They need to match.

How to Connect Strips Together

white strips and rgb connector

There are a couple of ways you can connect LED strip lights together. The easiest is to use a connector (Amazon), while the alternative is soldering the connections together yourself – a little more advanced, but it can be more reliable and efficient.

You also need to think about power.

The strips should be rated for the same voltage, and you need a power source with sufficient wattage to correctly power the length of your lights.

Any LED strip light should tell you how many Watts per meter it requires.

If you connect too many strip lights together, the LEDs furthest away from the power source may not get the power needed and may be dim.

It’s worth reading my guide on connecting LED strips together for more information on how to do it, and some of the other considerations.

What If My LED Strip Is Too Long, Can I Cut It?

cutting LED strip light

You can cut LED strips to a shorter length if they’re too long, but you must cut along the designated cutting lines. These are the safe points where you can cut an LED strip without damaging the circuitry of the light fixtures, so they’ll still work.

Just like you may end up buying LED strips that are too short, you can also find longer strips that are too long, or you may connect two strips together but end up with something bigger than you need.

As long as your LED strip lights have cutting lines – they can be dotted, dashed, or solid lines depending on the manufacturer – you can cut them, providing you cut along that line. Most LED strip lights have these.

Each cutting line represents the end of an individual circuit within the strip. Therefore, you don’t interrupt a circuit if you cut along that line.

Cutting elsewhere will cause that circuit to fail and potentially the whole strip.

You can also re-use the piece you’ve cut off, either by connecting it to a new power supply elsewhere or using a connector.

A lot of people will cut LED strips to use a corner connector to navigate an LED strip around a tight bend neatly.

Final Words

With the option to connect LED strips together and cut them to length, it’s pretty easy to make sure you get the right length for your room.

Whether you’re using them around the ceiling for task lighting, or you just want a smaller LED rope for accent lighting, follow these steps and you’ll be fine.

It’s just that first step of measuring the room accurately and then making sure that when buying LED strip lights, you choose compatible strips and your power source is sufficient to make sure they all work correctly.

If you want to know more about LED strip lights, including how to install them and how to find a quality light strip, my comprehensive guide to light strips will help.