function calculateBitRate() {
// Get Inputs
var sizeInput = parseFloat(document.getElementById('dataSize').value);
var unit = document.getElementById('sizeUnit').value;
var hours = parseFloat(document.getElementById('durHours').value) || 0;
var minutes = parseFloat(document.getElementById('durMinutes').value) || 0;
var seconds = parseFloat(document.getElementById('durSeconds').value) || 0;
// Validation
if (isNaN(sizeInput) || sizeInput <= 0) {
alert("Please enter a valid file size.");
return;
}
var totalSeconds = (hours * 3600) + (minutes * 60) + seconds;
if (totalSeconds <= 0) {
alert("Please enter a duration greater than zero.");
return;
}
// Convert Everything to Bits
// Using Binary prefixes for Storage (1 KB = 1024 Bytes)
// 1 Byte = 8 bits
var totalBits = 0;
switch(unit) {
case 'TB':
totalBits = sizeInput * 1024 * 1024 * 1024 * 1024 * 8;
break;
case 'GB':
totalBits = sizeInput * 1024 * 1024 * 1024 * 8;
break;
case 'MB':
totalBits = sizeInput * 1024 * 1024 * 8;
break;
case 'KB':
totalBits = sizeInput * 1024 * 8;
break;
case 'B':
totalBits = sizeInput * 8;
break;
}
// Calculate bits per second
var bps = totalBits / totalSeconds;
// Convert to standard decimal units for transmission rates (1 kbps = 1000 bps)
var kbps = bps / 1000;
var mbps = bps / 1000000;
var gbps = bps / 1000000000;
// Calculate Bytes per second (for download speed context)
var bytesPerSec = bps / 8;
var megabytesPerSec = bytesPerSec / (1024 * 1024);
// Display Results
document.getElementById('result-container').style.display = 'block';
document.getElementById('resKbps').innerText = formatNumber(kbps);
document.getElementById('resMbps').innerText = formatNumber(mbps);
document.getElementById('resGbps').innerText = formatNumber(gbps);
document.getElementById('resMBs').innerText = formatNumber(megabytesPerSec);
}
function formatNumber(num) {
if (num 0) {
return num.toExponential(2);
}
return num.toLocaleString('en-US', { minimumFractionDigits: 2, maximumFractionDigits: 2 });
}
How to Calculate Bit Rate: A Complete Guide
Understanding how to calculate bit rate is essential for video editors, network engineers, and streaming enthusiasts. Bit rate (or bitrate) determines the amount of data processed over a specific unit of time, directly impacting the quality of audio and video files as well as the bandwidth required for smooth transmission.
What is Bit Rate?
Bit rate represents the speed at which bits are transferred from one location to another. In the context of multimedia, it refers to the amount of data stored for each second of media.
Higher Bit Rate: Generally results in higher quality (less compression artifacts) but requires larger file sizes and faster internet connections.
Lower Bit Rate: Results in smaller files and easier streaming on slow connections, but often at the cost of image or sound clarity.
The Basic Formula
The most fundamental way to calculate bit rate involves knowing the total file size and the duration of the content. This is the formula used by the calculator above:
Bit Rate (bps) = (File Size in Bytes × 8) ÷ Duration in Seconds
Note: We multiply by 8 because file sizes are usually measured in Bytes, while speed is measured in bits.
Example Calculation
Let's say you have a video file that is 500 MB in size and runs for 10 minutes. Here is how you calculate the bit rate:
Convert Size to Bits: 500 MB = 500 × 1,024 × 1,024 Bytes = 524,288,000 Bytes. Multiply by 8 to get bits: 4,194,304,000 bits.
Convert Time to Seconds: 10 minutes = 600 seconds.
Divide: 4,194,304,000 bits ÷ 600 seconds = 6,990,506 bits per second (bps).
Convert to Mbps: 6,990,506 ÷ 1,000,000 ≈ 6.99 Mbps.
Calculating Uncompressed Audio Bit Rate
If you are working with uncompressed audio (like WAV files) and want to calculate the bit rate before the file is even created, you use a different physics-based formula:
Bit Rate = Sample Rate × Bit Depth × Number of Channels
For Streamers: If your upload speed is 10 Mbps, you cannot stream at a bit rate of 12 Mbps. Knowing how to calculate bit rate helps you configure OBS or streaming software to ensure your stream doesn't lag or drop frames.
For Storage: If you need to store 100 hours of footage on a hard drive, calculating the bit rate allows you to predict the total file size and purchase the correct amount of storage space.