function applyPreset() {
var preset = document.getElementById("resPreset").value;
if (preset !== "custom") {
var parts = preset.split(",");
document.getElementById("hRes").value = parts[0];
document.getElementById("vRes").value = parts[1];
}
}
function calculateDataRate() {
// Get inputs
var hRes = parseFloat(document.getElementById("hRes").value);
var vRes = parseFloat(document.getElementById("vRes").value);
var refresh = parseFloat(document.getElementById("refreshRate").value);
var bits = parseFloat(document.getElementById("bitDepth").value);
var chroma = document.getElementById("chromaSubsampling").value;
// Validation
if (isNaN(hRes) || isNaN(vRes) || isNaN(refresh)) {
alert("Please enter valid numbers for resolution and refresh rate.");
return;
}
// Determine Bits Per Pixel (bpp)
// 4:4:4 = 3 channels full depth
// 4:2:2 = effectively 2/3rds of the data of 4:4:4 (Average 2 components per pixel)
// 4:2:0 = effectively 1/2 of the data of 4:4:4
var bppBase = bits * 3; // Base for RGB/4:4:4
var bpp = bppBase;
if (chroma === "422") {
bpp = bits * 2;
} else if (chroma === "420") {
bpp = bits * 1.5;
}
// Calculations
var totalPixels = hRes * vRes;
// Raw Data Rate (Payload) in bits per second
var rawBitsPerSecond = totalPixels * refresh * bpp;
// Convert to Gbps
var dataRateGbps = rawBitsPerSecond / 1000000000;
// Estimate Total Signal Bandwidth (including Blanking)
// CVT-RB (Reduced Blanking) typically adds ~3-5% overhead
// Standard Blanking can add ~15-20%
// We will use a safe estimation factor of 1.15 to account for general blanking overheads
// This helps in selecting cables which rely on the total signal, not just active video.
var estimatedTotalGbps = dataRateGbps * 1.15;
// Display Results
document.getElementById("resultBox").style.display = "block";
document.getElementById("resPixels").innerText = totalPixels.toLocaleString() + " px";
document.getElementById("resBpp").innerText = bpp + " bits";
document.getElementById("resDataRate").innerText = dataRateGbps.toFixed(2) + " Gbps";
document.getElementById("resTotalSignal").innerText = "~" + estimatedTotalGbps.toFixed(2) + " Gbps";
// Cable Recommendations based on Total Bandwidth
var recText = "Recommendation: ";
var bw = estimatedTotalGbps;
if (bw <= 10.2) {
recText += "Standard HDMI 1.4 or DisplayPort 1.2 cables are sufficient.";
} else if (bw <= 18.0) {
recText += "Requires HDMI 2.0 (High Speed) or DisplayPort 1.2.";
} else if (bw <= 25.9) {
recText += "Requires DisplayPort 1.3 / 1.4 (HBR3). HDMI 2.0 is insufficient.";
} else if (bw <= 32.4) {
recText += "Requires DisplayPort 1.3 / 1.4 (Maxing out HBR3).";
} else if (bw <= 40.0) {
recText += "Requires HDMI 2.1 (Ultra High Speed – 40Gbps).";
} else if (bw <= 48.0) {
recText += "Requires HDMI 2.1 (Ultra High Speed – 48Gbps).";
} else if (bw <= 80.0) {
recText += "Requires DisplayPort 2.0 / 2.1 (UHBR 10/13.5/20). Likely requires DSC (Display Stream Compression) for HDMI.";
} else {
recText += "Bandwidth is very high. You will likely need Display Stream Compression (DSC) to transmit this signal over standard cables.";
}
document.getElementById("cableRec").innerHTML = recText;
}
What is Display Data Rate?
Display Data Rate refers to the amount of data usually measured in Gigabits per second (Gbps), required to transmit a video signal from a source (like a PC or gaming console) to a display (monitor or TV). Understanding this metric is critical when setting up high-performance workstations or gaming rigs, as it dictates the type of cable and interface standard you must use.
If the data rate of your desired resolution and refresh rate exceeds the bandwidth capacity of your cable (e.g., trying to push 4K 120Hz over an old HDMI 1.4 cable), you will experience a black screen, flickering, or the system will automatically downgrade your settings.
How Calculation Works
The bandwidth required for a display signal depends on four primary factors:
Resolution: The total number of pixels (Width × Height).
Refresh Rate: How many times per second the screen updates (e.g., 60Hz, 144 Hz).
Color Depth: The number of bits used to represent the color of a single pixel (e.g., 8-bit for SDR, 10-bit for HDR).
Chroma Subsampling: A compression technique that reduces color information to save bandwidth (e.g., 4:4:4 vs 4:2:0).
The Formula
The simplified formula to calculate the uncompressed video payload is:
The calculator above provides two numbers: the Uncompressed Data Rate (the raw video size) and the Estimated Total Signal. Real-world signals require extra data for timing (called blanking intervals). Standard blanking can add 15-20% overhead, while modern Reduced Blanking (CVT-RB) adds significantly less. Cables must support the Total Signal bandwidth.
Common Interface Bandwidth Limits
Use the table below to check if your calculated data rate fits your hardware interface:
Interface Standard
Max Transmission Rate
Typical Use Case
HDMI 1.4
10.2 Gbps
1080p 144Hz, 4K 30Hz
HDMI 2.0
18.0 Gbps
4K 60Hz, 1440p 144Hz
HDMI 2.1
48.0 Gbps
4K 120Hz, 8K 60Hz (with DSC)
DisplayPort 1.2
17.28 Gbps
4K 60Hz
DisplayPort 1.4
25.92 Gbps
4K 120Hz (often needs DSC for HDR)
DisplayPort 2.0 / 2.1
80.0 Gbps
Dual 4K, 8K, 16K
Frequently Asked Questions
What is Chroma Subsampling (4:4:4 vs 4:2:0)?
Chroma subsampling is a method of reducing bandwidth by sending less color resolution while keeping brightness resolution full. 4:4:4 sends full color data and is best for PC monitors where text clarity is important. 4:2:0 halves the color data; it is fine for movies but can make text look blurry on a desktop.
Does HDR increase bandwidth?
Yes. Standard Dynamic Range (SDR) typically uses 8-bit color. High Dynamic Range (HDR) usually requires 10-bit or 12-bit color. Going from 8-bit to 10-bit increases the data rate by 25%.
What is DSC?
Display Stream Compression (DSC) is a "visually lossless" compression algorithm used in HDMI 2.1 and DisplayPort 1.4/2.0. It allows you to push resolutions (like 8K or 4K 240Hz) that normally exceed the raw bandwidth of the cable.