You might have heard that HDMI cables can lose picture quality at certain lengths.
The truth is, since HDMI cables encounter signal degradation, there is a limit to HDMI cable length. But it’s not set in stone, and it also depends on the category of HDMI cable you use, as well as a couple of other factors, such as desired resolution.
How Long Can an HDMI Cable Be?
For resolutions near 4K, it’s recommended to use an HDMI cable that is no longer than 3 meters (10 feet). After that distance, the signal can start to degrade. For lower resolutions, the reliable distance is much longer, with the most common being 15 meters (50 feet).
I found myself wondering what is the maximum distance I can run an HDMI cable without running into any issues. In the next section, we’re going to breakdown what is the ideal length for these accessories, what resolution you can expect, and how to boost HDMI signals.
Generally, when it comes to HDMI cables, the shorter, the better. This is to prevent signal degradation which tends to occur around the 50-ft mark.
How Can I Tell If There Are Any Issues?
When it comes to cables, one of the most common mantras is, “It either works, or it doesn’t”. Sometimes, it’s not that simple. In some cases, a long cable will just be unreliable.
An HDMI cable can still work over long distances, but you might run into graphical artefacts, a loss of brightness, input lag, a low refresh rate, and other issues. When you start encountering those issues, you can bet that the cable is running into issues.
Basically, what happens is the cable sends the information that it can, which isn’t always the information that you’re expecting to receive. It’s pushing through 1s and 0s but sometimes not all the packets can make it to the end-point.
In simple terms: the further the signals have to travel, the weaker they get.
What is the Maximum Reliable Length?
While there are many different types of HDMI cables, most of them start to encounter signal degradation around the 15-meter mark (50 feet). To push it further, you’ll need the help of extra tools and cables, which we’ll talk about in the next section.
Another thing to keep in mind is that sharp bends can degrade the signal further. In short, if you’re planning to run an HDMI cable through your home, the end result might be either a completely blank screen, or a low-quality image.
There are a few solutions to that problem.
Is There a Maximum HDMI Length for 4K?
Since 4K requires a lot of bandwidth, most cables cannot transfer the resolution over distances of more than three meters.
In some cases, the distance will be much shorter, around the one to two-meter mark. The longer the cable, the lower the resolution. If you want to get the absolute best resolution, make sure the HDMI cable is no longer than necessary.
To guarantee the best 4K experience, we recommend looking for cables that are labelled “High Speed” and never get one longer than three meters.
How Can I Extend The Length?
If you’re sure the length is causing signal degradation, then there are a few steps you can take to boost the signal distance.
Use a Signal Booster (Repeater)
One option would be to buy a small device called an HDMI signal booster, also known as an HDMI repeater. What these devices do is, in simple terms, add more power to the cable, to boost the digital signal. The devices strengthen the HDMI digital signals. They have an HDMI input and output, and an external port for power, usually micro-USB.
What you do is plug the signal booster into a power source, and then plug an HDMI into either end. These signals can boost the usable distance of cables.
One tip to remember is you need to add them to a section where the signal is still clear, it won’t be able to boost a low-quality signal. The effectiveness of the repeaters varies, but it usually falls within 10 to 15 meters.
For example, you can run a 15-meter cable from your computer to repeater, connect another 15-meter cable to that repeater, and finally to a display. This solution works okay for outdoor projectors or digital signage.
Use HDMI to Cat5 or Cat6 Adapters
To extend an HDMI cable, another option is to use a Cat5 or Cat6 cable. This option isn’t the best because you need two Cat cables to transfer the signal from one HDMI cable. That creates a lot of cables. I would only recommend this if you already have Cat cables lying around that are not in use.
But if you absolutely need to send an HDMI signal over Cat cables, then you can buy HDMI to Cat adapter. It’s a little tricky to get working and you need two long-distance Cat cables, but it can work.
Fibre Optic HDMI Cables
Regular copper HDMI cables have a number of limitations, such as the distance signals can transfer without losing data. However, there’s another type of HDMI cable made from fibre optics.
The technology is quite different. Regular HDMI cables transmit electricity through copper, while optical cables transmit light waves through fibre-glass. You probably already guessed which one can transfer data further.
Active Fibre optic HDMI cables (AOC) can carry digital information much further than copper HDMI cables, and they have great protection against outside interference too. Another reason people prefer these HDMI cables is that the wires are more flexible, so they’re easier to install and cable manage.
Most people also report that fibre optic cables, when compared to the usual copper ones, transmit clearer images with more colour, at the same lengths. Generally, with fibre optic HDMI, the signals are much stronger and can be pushed further because the technology doesn’t allow the signal to degrade. While there are many pros to using fibre optic HDMI cables, there are also some downsides too.
What’s the Maximum Length for a Fibre Optic HDMI Cable?
It’s unclear what the maximum range of fibre optical HDMI cables is because most merchants sell them in specific bundles, from 3-ft to 200 ft. Technically, fibre optic cables can run for miles, maybe 40 to 60 miles, but most manufacturers won’t make HDMI cables in those lengths. Generally, fibre optic HDMI has almost no signal loss over distance.
The effective range is much better than regular HDMI cables, which start to run into issues around the 50 ft mark. So if you need to run an HDMI cable over a long distance, fibre optic is definitely the best, albeit expensive, choice.
The Downsides to Fiber Optic HDMI Cables
Before you go ahead and buy a fibre optic HDMI cable, there are a couple of things you need to know. For starters, they’re a bit more expensive than regular HDMI cables, especially certain brands.
However, the difference is not that much, usually between £10 to £20 more than copper cables of the same length. Thankfully, the price of fibre optics has come down a lot in the past few years, it used to be well out of the average person’s budget.
Secondly, almost all fibre optic HDMI cables are one-way. What that means is one side (the appropriate ends are usually labelled as “Display” and “Source”) needs to be connected to the item on the label. Unlike regular HDMI cables, they’re not backwards compatible, so you need to make sure you plug them in the right direction.
Other than that, if you need the longest and most stable HDMI cable, I would pick a fibre optic cable. In the long-run, the investment is well worth it.
Wrapping it Up
Overall, if you need to run an HDMI cable over long distances, I recommended looking for an active fibre optic HDMI cable. Otherwise, you can use separate HDMI cables connected through HDMI repeaters.
Just remember, at long distances, you shouldn’t expect absolutely perfect performance. The visuals might be okay but you could encounter input lag and other issues. Generally, for media-watching, it’s not a problem.