Refresh Rate Calculator
Find the bandwidth and cable needed for any resolution and refresh rate, with HDMI and DisplayPort support from 1080p 144Hz to 4K 240Hz.
How the refresh rate calculator works
A display connection has to carry every pixel, every frame. The raw bandwidth a monitor needs is its pixel count multiplied by the refresh rate and the colour depth of each of the three colour channels, converted from bits to gigabits per second:
bandwidth (Gbps) = width × height × Hz × bits-per-channel × 3 ÷ 1,000,000,000
We then add roughly 10% for transmission overhead. HDMI and DisplayPort do not send raw pixel data — they wrap it in line encoding (8b/10b on older DisplayPort, 16b/18b on newer standards) plus blanking intervals, so the real figure on the wire is always higher than the arithmetic suggests. The result is compared against the certified maximum of every common cable standard to find the cheapest one that can carry your signal.
Why the cable matters
Plugging a 4K 144 Hz monitor into an HDMI 2.0 port does not usually produce an error message. Instead the display silently drops to a lower refresh rate, falls back to 8-bit colour, or switches to chroma subsampling (4:2:2 or 4:2:0), which makes text look fringed and blurry. If your monitor is not hitting its advertised numbers, the cable or the port is the first thing to check.
Display Stream Compression (DSC)
When a signal exceeds the cable's limit, DisplayPort 1.4 and HDMI 2.1 can apply DSC, a visually lossless compression scheme with roughly a 3:1 ratio. This is how 4K 240 Hz works over a DisplayPort 1.4 cable that could not otherwise carry it. Both the GPU and the monitor must support DSC, and some older GPUs disable multi-monitor features when it is active.
Refresh rate and frame rate are different things
The refresh rate is the ceiling your monitor can display; the frame rate is what your GPU actually delivers. A 240 Hz panel fed 90 fps shows 90 unique frames a second. Use the FPS Calculator to estimate what your hardware can sustain, and the Bottleneck Calculator to check whether your CPU or GPU is the limiting factor.
Frequently asked questions
What cable do I need for 4K 144Hz?
3840x2160 at 144Hz with 8-bit colour needs roughly 31.5 Gbps, which just fits inside DisplayPort 1.4 (32.4 Gbps) and sits comfortably within HDMI 2.1 (48 Gbps). At 10-bit for HDR the requirement rises to about 39.4 Gbps, which exceeds DisplayPort 1.4 and needs either HDMI 2.1 or DSC.
Can HDMI 2.0 do 1440p 144Hz?
2560x1440 at 144Hz with 8-bit colour needs about 14 Gbps and HDMI 2.0 carries 18 Gbps, so yes, with room to spare. Moving to 10-bit colour pushes it to roughly 17.5 Gbps, which still fits but leaves almost no margin.
Does a more expensive cable give me more bandwidth?
No. Bandwidth is set by the standard the cable is certified to, not by its price. A certified Ultra High Speed HDMI cable carries 48 Gbps whether it costs 8 dollars or 80. What you pay more for is build quality and reliable performance at longer lengths.
Why is my monitor stuck at 60Hz?
The usual causes are a cable or port that cannot carry the bandwidth, a refresh rate that was never selected in the OS display settings, or the monitor being connected to the motherboard's video output rather than the graphics card.
Is 10-bit colour worth the extra bandwidth?
Only if your monitor genuinely supports HDR with a reasonable peak brightness. On an SDR panel, 10-bit input gains you almost nothing while consuming 25% more bandwidth, which may force a lower refresh rate.