*Values are estimates based on Apple's target bitrates. Actual sizes may vary based on content complexity.
Understanding Apple ProRes 422 Data Rates
Apple ProRes 422 is a post-production codec standard developed by Apple. It is a "visually lossless" format, meaning it preserves high image quality while significantly reducing file sizes compared to uncompressed raw video. However, because it is an intermediate codec designed for high-performance editing, its data rates are much higher than delivery formats like H.264 or HEVC.
Key Factors Influencing ProRes File Size
ProRes Flavor: There are four main variants within the 422 family. HQ (High Quality) offers the highest bitrate, while Proxy is intended for lightweight editing on older systems.
Resolution: Moving from 1080p to 4K UHD quadruples the number of pixels, which significantly increases the data rate required to maintain quality.
Frame Rate: A 60fps video contains twice as many frames per second as a 30fps video, resulting in roughly double the storage requirement.
ProRes 422 Flavor Comparison
This calculator uses standard target bitrates at 1080p/29.97fps as the baseline for scaling:
Flavor
Target Bitrate (1080p/29.97)
Typical Use Case
ProRes 422 HQ
220 Mbps
High-end mastering & VFX
ProRes 422
147 Mbps
General high-quality editing
ProRes 422 LT
102 Mbps
Documentaries / Fast turnarounds
ProRes 422 Proxy
45 Mbps
Offline editing workflows
Real-World Example
If you are shooting a 60-minute interview in 4K UHD (3840×2160) at 23.976 fps using ProRes 422 HQ, you can expect a total file size of approximately 318.5 GB. This demonstrates why choosing the correct flavor and having sufficient high-speed storage (like NVMe SSDs or RAID arrays) is critical for professional video production.
function updateCustomVisibility() {
var res = document.getElementById("resolution").value;
var customFields = document.getElementById("custom-res-fields");
if (res === "custom") {
customFields.style.display = "grid";
} else {
customFields.style.display = "none";
}
}
function calculateProRes() {
// Get Inputs
var resType = document.getElementById("resolution").value;
var width, height;
if (resType === "custom") {
width = parseFloat(document.getElementById("customWidth").value);
height = parseFloat(document.getElementById("customHeight").value);
} else {
var dims = resType.split("x");
width = parseFloat(dims[0]);
height = parseFloat(dims[1]);
}
var flavor = document.getElementById("flavor").value;
var fps = parseFloat(document.getElementById("fps").value);
var h = parseFloat(document.getElementById("hours").value) || 0;
var m = parseFloat(document.getElementById("mins").value) || 0;
var s = parseFloat(document.getElementById("secs").value) || 0;
// Total seconds
var totalSeconds = (h * 3600) + (m * 60) + s;
// Base bitrates for 1080p @ 29.97 fps (Mbps)
var baseBitrate = 0;
if (flavor === "422hq") baseBitrate = 220;
else if (flavor === "422") baseBitrate = 147;
else if (flavor === "422lt") baseBitrate = 102;
else if (flavor === "422proxy") baseBitrate = 45;
// Math to scale bitrate
// Bitrate scales linearly with number of pixels and frame rate
var pixelRatio = (width * height) / (1920 * 1080);
var fpsRatio = fps / 29.97;
var calculatedBitrateMbps = baseBitrate * pixelRatio * fpsRatio;
// Calculate size
// Megabits to Megabytes (divide by 8)
var sizeMB = (calculatedBitrateMbps / 8) * totalSeconds;
var sizeDisplay = "";
if (sizeMB >= 1048576) {
sizeDisplay = (sizeMB / 1048576).toFixed(2) + " TB";
} else if (sizeMB >= 1024) {
sizeDisplay = (sizeMB / 1024).toFixed(2) + " GB";
} else {
sizeDisplay = sizeMB.toFixed(2) + " MB";
}
// Update DOM
document.getElementById("bitrate-result").innerText = Math.round(calculatedBitrateMbps) + " Mbps";
document.getElementById("filesize-result").innerText = sizeDisplay;
document.getElementById("results-area").style.display = "block";
// Scroll to results
document.getElementById("results-area").scrollIntoView({ behavior: 'smooth', block: 'nearest' });
}