Converts Mbps, Gbps, Kbps into MB/s, GB/s, KB/s on webpages (works in real-time on fast.com, speedtest.net, ISP offers, etc.)
// ==UserScript==
// @name Bandwidth Unit Converter (bits → bytes)
// @namespace spotlightforbugs.scripts.bandwidth
// @version 1.3
// @description Converts Mbps, Gbps, Kbps into MB/s, GB/s, KB/s on webpages (works in real-time on fast.com, speedtest.net, ISP offers, etc.)
// @author SpotlightForBugs
// @license MIT
// @match *://*/*
// @grant none
// ==/UserScript==
(function () {
"use strict";
// Conversion factors (bits → bytes)
const conversions = {
Kbps: { factor: 1 / 8, unit: "KB/s" },
Mbps: { factor: 1 / 8, unit: "MB/s" },
Gbps: { factor: 1 / 8, unit: "GB/s" },
Tbps: { factor: 1 / 8, unit: "TB/s" },
"kbit/s": { factor: 1 / 8, unit: "KB/s" },
"Mbit/s": { factor: 1 / 8, unit: "MB/s" },
"Gbit/s": { factor: 1 / 8, unit: "GB/s" },
};
function convertTextNode(node) {
let text = node.nodeValue;
if (!text) return;
// Match "100 Mbps" style
const regex = new RegExp(
"(\\d+(?:\\.\\d+)?)\\s*(" + Object.keys(conversions).join("|") + ")",
"gi"
);
node.nodeValue = text.replace(regex, (match, value, unit) => {
if (match.includes("(")) return match; // already converted
const num = parseFloat(value);
const { factor, unit: newUnit } = conversions[unit];
const converted = (num * factor).toFixed(2);
return `${match} (${converted} ${newUnit})`;
});
}
function handleSeparatedUnits(node) {
// Look for patterns like: <span>247.04</span><span>Mbps</span>
if (
node.nodeType === 1 &&
node.nextSibling &&
node.nextSibling.nodeType === 1
) {
const numText = node.textContent.trim();
const unitText = node.nextSibling.textContent.trim();
if (conversions[unitText] && !node.nextSibling.dataset.converted) {
const num = parseFloat(numText);
if (!isNaN(num)) {
const { factor, unit } = conversions[unitText];
const converted = (num * factor).toFixed(2);
node.nextSibling.textContent =
unitText + ` (${converted} ${unit})`;
node.nextSibling.dataset.converted = "true";
}
}
}
}
function walk(node) {
let child, next;
switch (node.nodeType) {
case 1: // Element
handleSeparatedUnits(node);
// fallthrough
case 9: // Document
case 11: // Document fragment
child = node.firstChild;
while (child) {
next = child.nextSibling;
walk(child);
child = next;
}
break;
case 3: // Text node
convertTextNode(node);
break;
}
}
// Initial run
walk(document.body);
// Observe changes (for dynamic content like fast.com, speedtest.net)
const observer = new MutationObserver((mutations) => {
mutations.forEach((mutation) => {
mutation.addedNodes.forEach((node) => {
walk(node);
});
if (mutation.type === "characterData") {
walk(mutation.target);
}
});
});
observer.observe(document.body, {
childList: true,
subtree: true,
characterData: true,
});
})();
/*
MIT License
Copyright (c) 2025 SpotlightForBugs
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/