Display Bandwidth Calculator
Work out how much bandwidth your resolution, refresh rate and color depth actually need, and which cable and port versions can carry it. This is why a monitor sometimes refuses to run at its advertised refresh rate.
Resolution
Refresh rate
Color depth
Chroma subsampling
Full color, required for sharp text
Bandwidth required
38.40 Gbps
3840x2160 at 144Hz, 10-bit, 4:4:4
- HDMI 1.48.16 Gbps
- HDMI 2.014.4 Gbps
- HDMI 2.142.67 Gbps
- DisplayPort 1.2 (HBR2)17.28 Gbps
- DisplayPort 1.4 (HBR3)25.92 Gbps
- DisplayPort 2.1 UHBR 1038.69 Gbps
- DisplayPort 2.1 UHBR 13.552.22 Gbps
- DisplayPort 2.1 UHBR 2077.37 Gbps
Figures are effective payload bandwidth after encoding overhead, which is what actually carries your picture, not the raw link rate printed on the box.
How this is calculated
- Bandwidth is total pixels including blanking intervals, times refresh rate, times bits per pixel. Blanking uses CVT reduced-blanking timing, so the figure is a close estimate rather than an exact match for every monitor.
- Chroma subsampling lowers the bits each pixel costs: 4:4:4 is full color, 4:2:2 is two thirds, and 4:2:0 is half.
- Port figures are effective bandwidth after line encoding: 8b/10b costs 20 percent, HDMI 2.1 16b/18b costs about 11 percent, and DisplayPort UHBR 128b/132b costs about 3 percent.
- DSC compresses roughly 3:1 and is treated as visually lossless by VESA, which is how 4K at high refresh fits over DisplayPort 1.4.
Testing guide
How to work out display bandwidth
Every combination of resolution, refresh rate, color depth and chroma format has a bandwidth cost. If that cost exceeds what your cable and ports can carry, the display silently falls back: lower refresh rate, 8-bit instead of 10-bit, or subsampled color that makes text look smeared.
Best for
- Finding out why a monitor will not run at its advertised refresh rate.
- Choosing the right cable and port version before buying a high refresh or HDR display.
- Understanding whether you need DSC to reach a given mode.
How to run the test
- 1Pick your native resolution and the refresh rate you actually want to run.
- 2Choose 10-bit if you want HDR, since it costs 25 percent more bandwidth than 8-bit.
- 3Leave chroma on 4:4:4 for desktop use, since anything lower degrades text.
- 4Compare the result against the port list to see which versions can carry it.
How to read the result
A green tick means that port version carries the mode uncompressed.
If nothing green is available, enable DSC and check again; that is how 4K at high refresh fits over DisplayPort 1.4.
If your hardware supports the mode on paper but not in practice, the cable is usually the limiting factor rather than the ports.
Related tools and guides
Frequently asked questions
How much bandwidth does 4K 144Hz need?
Roughly 38 to 40 Gbps at 10-bit 4:4:4 uncompressed, depending on the blanking timing used. That exceeds DisplayPort 1.4 at 25.92 Gbps effective, which is why this mode requires either DSC compression or a DisplayPort 2.1 UHBR connection.
Why does my monitor not reach its advertised refresh rate?
Almost always a bandwidth limit somewhere in the chain. The cable may not be rated for the mode, the port may be an older version than the panel supports, or a hub or adapter in between may be the bottleneck. Lowering color depth or enabling DSC usually confirms it.
What is DSC and is it lossless?
Display Stream Compression is a VESA standard that compresses the video stream by roughly 3:1. VESA classifies it as visually lossless, meaning the difference is not perceptible in normal viewing, though it is not mathematically lossless. It is how most 4K high refresh setups work today.
Does HDR need more bandwidth?
Yes. HDR normally means 10-bit color instead of 8-bit, which is 25 percent more data per pixel. That is enough to push some modes past what a cable can carry, which is why enabling HDR sometimes forces the refresh rate down.
Why are the port numbers lower than the ones on the box?
Manufacturers quote raw link rate, but part of that is consumed by line encoding. DisplayPort up to HBR3 uses 8b/10b, which spends 20 percent on encoding, so a 32.4 Gbps link carries 25.92 Gbps of picture. This calculator uses the effective figures, since that is what actually has to fit your signal.