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
The signal also carries blanking intervals between lines and frames. We use the CVT-R2 reduced-blanking timing that high-refresh monitors run at — an 80-pixel gap after every line and at least 460 µs between frames — which is why the overhead grows at high refresh rates, where that fixed gap takes a bigger share of each frame.
The result is compared with each standard's data rate, not its headline link rate. Line encoding takes its share before any pixel is sent — 8b/10b on HDMI 2.0 and DisplayPort 1.4, 16b/18b on HDMI 2.1, 128b/132b on DisplayPort 2.1 — so DisplayPort 1.4's 32.4 Gbps link carries 25.92 Gbps of picture, and HDMI 2.0's 18 Gbps carries 14.4.
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 about 31.3 Gbps. That is more than DisplayPort 1.4 carries (25.92 Gbps of data), so over DP 1.4 it only works with DSC compression. HDMI 2.1 (42.6 Gbps) or DisplayPort 2.1 UHBR10 (38.7 Gbps) carry it uncompressed. At 10-bit for HDR it rises to about 39.2 Gbps, which still fits HDMI 2.1.
Can HDMI 2.0 do 1440p 144Hz?
Yes, just. 2560x1440 at 144Hz with 8-bit colour needs about 14.1 Gbps, and HDMI 2.0 carries 14.4 Gbps of data. There is no room for 10-bit colour, which needs about 17.6 Gbps - for HDR at 144Hz use DisplayPort 1.4 or HDMI 2.1 instead.
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.