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Display Cable Bandwidth Calculator

Works out the data rate a resolution, refresh rate and colour depth needs, then names the HDMI or DisplayPort version that carries it.

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Lab tool
Enter your figures and press Calculate bandwidth.
In short A display mode needs a data rate, and the cable standard either carries it or it does not. Resolution times refresh rate times bits per pixel gives the raw figure, plus the blanking overhead the signal format adds. HDMI 1.4 carries 8.16 Gbit/s, HDMI 2.0 carries 14.4, HDMI 2.1 carries 42.6, and DisplayPort 1.4 carries 25.92 — which is why 4K at 120 Hz in 10-bit colour is comfortable on one of those and impossible on another. The common frustration is a monitor and a graphics card that both say HDMI 2.1 while the connection runs at 60 Hz, and the answer is nearly always the cable: HDMI 2.1 bandwidth requires an Ultra High Speed certified cable, and an older one will link-train down to whatever it can manage without telling you. DSC changes the arithmetic substantially — it is a visually lossless compression that roughly triples the effective capacity, and modes that look impossible on paper become available when both ends support it. Chroma subsampling at 4:2:0 also fits a mode into a smaller pipe, but it does so by throwing away colour resolution, and it makes small text visibly fringed. Take DSC before subsampling.

How to use the Display Cable Bandwidth Calculator

  1. Enter your figures in the input fields.
  2. The result updates as you type, together with the full working.
  3. Check the breakdown table to see exactly how the number was reached.

About the Display Cable Bandwidth Calculator

The Display Cable Bandwidth Calculator works out the data rate a resolution, refresh rate and colour depth needs, then names the HDMI or DisplayPort version that carries it. It runs as plain JavaScript inside the page, which means there is no upload step, no queue and no size limit imposed by a server — the only limit is your own device.

What people use it for

  • Finding out whether your cable or your port is the reason a refresh rate is missing.
  • Choosing between HDMI and DisplayPort for a new monitor.
  • Working out whether 10-bit colour is what is costing you 144 Hz.

Details

HDMI 1.48.16 Gbit/s
HDMI 2.014.4 Gbit/s
HDMI 2.142.6 Gbit/s
DisplayPort 1.425.92 Gbit/s
DisplayPort 2.1 UHBR2077.37 Gbit/s

The maths behind it

This tool uses width × height × refresh × bits per channel × chroma factor × blanking overhead, divided by any compression ratio. Every intermediate value is shown on screen, so the result can be checked by hand.

Where this tool stops

A model of the standards, not a measurement of your equipment. Real links also carry audio and control data, and some manufacturers cap modes in firmware regardless of available bandwidth.

Explained in our guides

All guides

Frequently asked questions

My monitor and GPU both say HDMI 2.1 but I only get 60 Hz.
The cable. HDMI cables are rarely labelled clearly and an older one will negotiate down to 2.0 speeds silently. Try a cable certified as Ultra High Speed, and check that the monitor's own menu has the higher HDMI mode enabled — many ship with it off by default.
What is DSC and why does it change the answer so much?
Display Stream Compression, a visually lossless 3:1 compression built into DisplayPort 1.4 and HDMI 2.1. It is how DisplayPort 1.4 drives 4K at 144 Hz when the raw arithmetic says it cannot. Both ends must support it.
Should I use 4:2:0 to fit a mode in?
Not for a computer monitor. Chroma subsampling throws away colour resolution, which is invisible in video and very visible in small text — coloured fringing on letters is the classic symptom. Drop to 8-bit colour before dropping chroma.
Why does the calculator add blanking overhead?
Displays send more data than the visible pixels, in intervals originally needed for the electron beam to return. Modern reduced-blanking timings add about 5%; older CVT timings add around 25%, which is enough to push a mode over a link's limit.
Is there a limit on how often I can use the Display Cable Bandwidth Calculator?
Free, unlimited, and no email address required. You can use it a hundred times a day and nothing changes.
Is my data uploaded anywhere?
No. The Display Cable Bandwidth Calculator runs entirely in your browser using JavaScript. Nothing is transmitted, logged or stored, which you can verify yourself in the Network tab of your browser's developer tools.
How is the result calculated?
It uses width × height × refresh × bits per channel × chroma factor × blanking overhead, divided by any compression ratio. The full working is printed under the result, so you can follow every step rather than trusting a black box.
What do people use the Display Cable Bandwidth Calculator for most?
The jobs it is built for: finding out whether your cable or your port is the reason a refresh rate is missing. Choosing between HDMI and DisplayPort for a new monitor. Working out whether 10-bit colour is what is costing you 144 Hz. It is built for exactly those cases rather than being a general-purpose tool with this bolted on.
Is there anything the Display Cable Bandwidth Calculator cannot do?
A model of the standards, not a measurement of your equipment. Real links also carry audio and control data, and some manufacturers cap modes in firmware regardless of available bandwidth. Knowing where a tool stops being trustworthy matters more than the cases where it works.
What figures does the Display Cable Bandwidth Calculator work from?
HDMI 1.4 is 8.16 Gbit/s. HDMI 2.0 is 14.4 Gbit/s. HDMI 2.1 is 42.6 Gbit/s. These are printed on the page itself, so you do not have to take them on trust.
How precise is the result?
The calculation runs in double precision and the result is shown to ten significant figures, so converting a value and converting it back returns the original. What is displayed is rounded for readability; what is copied is not.

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