The answer to the question “does HDMI support 120Hz” is a resounding yes, HDMI cables CAN support 120Hz refresh rate. However, you should note that there are different HDMI interface versions. Newer versions have a higher bandwidth and thus can support a higher refresh rate and resolution.
In other words, whether the HDMI interface would be able to support 120Hz refresh rate depends upon its version, as well as on the resolution you are planning on running your monitor at.
For instance, if you have an older HDMI 1.4 interface, it would be able to support FHD at 120Hz without any issue, however, the same cannot be said if you plan to run 4K resolution on it.
In the following text I will explain in detail whether HDMI supports 120Hz refresh rate or not and if so at what resolution and color bit depth.
What are the Different HDMI Versions?
HDMI interface has been evolving owing to the fact that demands of the output devices are ever increasing. While a decade ago Full HD resolution and 60 Hz refresh rate was the norm.
Today, you can find display devices easily offering QHD, 4K and even 8K resolution at 120Hz or higher refresh rates.
Hence, the older HDMI interface version released a decade that were designed for FHD @ 60Hz are simply not enough to cater to the demands of the newer display devices.
The following table explains the popular HDMI versions and their respective specs.
|HDMI Version||Max Resolution||Max Refresh Rate||Max Bandwidth|
|HDMI 1.0||1080p||1080p @ 60 Hz||4.95||3.96||No||- 8 Audio Channels|
|HDMI 1.1/1.2||1440p||1440p @ 30 Hz||4.95||3.96||No||- 8 Audio Channels
-Super Audio CDs
|HDMI 1.3/1.4||4096 x 2160 (4K)||120 Hz @ FHD Resolution|
30 Hz @ 4k Resolution
24 Hz @ 4k Resolution
|10.2||8.16||No||- 8 Audio Channels
- Dolby TrueHD
|HDMI 2.0||4096 x 2160 (4K)||60 Hz @ 4K Resolution||18||14.40||Yes||- 32 audio channels,
- Dynamic Resolution Adaptation (DRA)
- High-Efficiency Advanced Audio Coding (HE-AAC)
|HDMI 2.1||Upto 10240 x 4320 (10K)||Upto 120Hz @ 10K||48||42.67||Yes||- 32 audio channels
Higher Display Device Specs = Higher Data Rate
One of the key aspects you need to understand is that the higher the specs of a display device like a monitor or a TV, the more data it would generate. Nominally, the data a display device generates is dictated by three key attributes:
- Refresh Rate
- Color Bit Depth
Higher resolution would generation more data. The same goes for refresh rate.
Color bit depth defines the amount of colors the display can show. Average monitors and TVs have an 8-bit display. Meaning they can show 16.7 million colors. Professional displays have 10 or higher color depth. 10-bit = 1 billion colors.
Calculating Your Data Rate
So in order to check if your HDMI interface can support your desired refresh rate, resolution and color depth, you can use a simple equation as follows:
(H + Hblank) × (V + Vblank) × (C x 3) × F
In this equation,
- H is horizontal pixel count
- V is vertical pixel count
- C is the color depth
- F is the refresh rate
- Hblank is the Horizontal blanking interval
- Vblank is the Vertical blanking Interval
Blanking intervals are basically the time periods it takes the display device to go from the end of the scan to the beginning of the scan. These are different for different resolution and refresh rate. For FHD @ 120Hz they are as follows:
- Hblank = 80 pixels for FHD @ 120 Hz
- Vblank = 60 Pixels for FHD @ 120 Hz
You can also save yourself from the hassle of manual calculation using popular calculators such as this one.
So Does HDMI Support 120Hz?
With the knowledge of the different HDMI version ports as well as of how to calculate your data rate, you can verify whether your interface will be able to support 120Hz refresh rate or not.
Lets do a practical example. Say I have a Full HD monitor with 8 bit color depth and I want to operate at 120Hz refresh rate.
Taking the equation above, we get
(H + Hblank) × (V + Vblank) × (C x 3) × F
= (1920 + 80) × (1080 + 60) × (8 x 3) × 120
= 6,566,400,000 bits per second = 6.58 Gbits/s
We know that the HDMI 1.4 can support upto 8.16 Gbit/s of effective data rate, and hence at FHD resolution ad with an 8-bit color depth, you should have no issue using the old HDMI 1.4 interface which is found on even decade old monitors and PCs.
The following table summarizes the version of HDMI you would need in order to operate 120Hz at different resolution and color bit depth.
|120Hz||1920x1080 (FHD)||8||6.58||HDMI 1.4|
|120Hz||2560x1440 (QHD)||8||11.59||HDMI 2.0|
|120Hz||3840x2160 (UHD/4K)||8||54.97||HDMI 2.1|
|120Hz||1920x1080 (FHD)||10||8.24||~HDMI 1.4|
|120Hz||2560x1440 (QHD)||10||14.49||HDM 2.1|
|120Hz||3840x2160 (UHD/4K)||10||32.27||HDMI 2.1|
Wrong HDMI Interface Would Present Bottlenecks
While the HDMI interface is backwards compatible meaning you can plug a monitor with an HDMI 2.0 to a PC with an HDMI 1.4, or a TV with an HDMI 2.0 to a home theater system with an HDMI 1.4, using a newer device input device (TV/monitors) with an older output device (PC/console), you would be presenting bottlenecks.
In other words, if a TV is designed to display 4K @ 60 Hz and you simply connect to a console with an HDMI 1.4, the TV will not work at its full potential.
Also Read: Can I Plug HDMI 2.1 Cable Into a 1.4 Port?
Does HDMI 1.4 Support 120Hz?
HDMI 1.4 can only definitively support 120Hz at FHD with an 8 bit monitor.
It may be able to support 120Hz also at 2560×1080 (ultrawide screen HD) with an 8 bit monitor too, but there may be some lags and stutters most of which would go unnoticed.
Does HDMI 2.0 Support 120Hz?
Yes, it does. HDMI 2.0 can support 120 Hz refresh rate for 8-bit and 10-bit widescreen Full HD displays i.e 1080P, as well as for 8-bit ultrawide screen QHD displays i.e 1440p.
Does HDMI 2.0 Support 120Hz 1080P?
Yes, quite easily. HDMI 2.0 can support well beyond 120Hz @ 1080p resolution
Does HDMI 2.0 Support 120Hz 1440P?
Yes, it quite easily can. If you have an average TV or a monitor with an 8 bit color depth, then sure, 120Hz at 1440P would not be an issue at all.
If you have a professional grade 10-bit monitor, then you are pushing the limit, but still HDMI 2.0 should be able to support it quite well.
Do You Need HDMI 2.1 for 120Hz Gaming?
No, you need to have an HDMI 2.1 interface for 120Hz gaming UNLESS you wish to game on 4K monitors.
Also Read: Can HDMI Support 3440×1440 Resolution?
So, in the end, the answer to the question “does HDMI support 120Hz” is a yes on the surface. However, in order to get the in-depth answer, you have to check the resolution you wish to run your monitor/TV at and also the color bit depth of your display.
In majority of the cases, I would recommend you have the HDMI 2.0 interface to run 120Hz refresh rate. However, the older HDMI 1.4 interface can also suffice particularly when running at Full HD resolution.