Any quick way to see the lowest equivalent ratio of either the document size or object size?

The following script is for a single active layer – otherwise, it will report on the document:

/*
Photoshop Active Layer or Document Dimensions - Aspect Ratio.jsx
v1.0, Stephen Marsh 31st January 2025
Based on:
https://github.com/MarshySwamp/Photoshop-Document-Dimensions---MP-Value---Aspect-Ratio/blob/main/Photoshop%20Document%20Dimensions%20-%20MP%20Value%20-%20Aspect%20Ratio.jsx
*/

#target photoshop

// Check for an active layer by jazz-y
s2t = stringIDToTypeID;
(r = new ActionReference()).putProperty(s2t('property'), p = s2t('targetLayers'));
r.putEnumerated(s2t("document"), s2t("ordinal"), s2t("targetEnum"));
if (executeActionGet(r).getList(p).count) {

    var savedRuler = app.preferences.rulerUnits;
    app.preferences.rulerUnits = Units.PIXELS;

    var bounds = app.activeDocument.activeLayer.bounds;

    var w = bounds[2].value - bounds[0].value; // Width based on layer bounds
    var h = bounds[3].value - bounds[1].value; // Height based on layer bounds
    var r = gcd(w, h);
    var ratio = w / h;

    alert(
        'Layer Dimensions: ' + w + ' x ' + h + ' pixels' + '\n' +
        'Aspect Ratio:' + '\n' + ratio.toFixed(2) + ':1' + ' / ' + ratio.toFixed(2) * 2 + ':2 / ' + ratio.toFixed(2) * 4 + ':4' + ' (Basic)' + '\n' +
        w / r + ':' + h / r + ' (GCD)' + '\n' +
        aspect_ratio(w / h, 50).toString().replace(',', ':') + ' (Farey)'
    );

    app.preferences.rulerUnits = savedRuler;

    function gcd(a, b) {
        /* https://stackoverflow.com/questions/1186414/whats-the-algorithm-to-calculate-aspect-ratio-i-need-an-output-like-43-169 */
        return (b == 0) ? a : gcd(b, a % b);
    }

} else {
    // Fallback to document dimensions if no layer is active
    var savedRuler = app.preferences.rulerUnits;
    app.preferences.rulerUnits = Units.PIXELS;

    var doc = app.activeDocument;
    var w = doc.width.value; // Width based on document dimensions
    var h = doc.height.value; // Height based on document dimensions
    var r = gcd(w, h);
    var ratio = w / h;

    alert(
        'Document Dimensions: ' + w + ' x ' + h + ' pixels' + '\n' +
        'Aspect Ratio:' + '\n' + ratio.toFixed(2) + ':1' + ' / ' + (ratio.toFixed(2) * 2) + ':2' + ' / ' + (ratio.toFixed(2) * 4) + ':4' + ' (Basic)' + '\n' +
        (w / r) + ':' + (h / r) + ' (GCD)' + '\n' +
        aspect_ratio(w / h, 50).toString().replace(',', ':') + ' (Farey)'
    );

    app.preferences.rulerUnits = savedRuler;

    function gcd(a, b) {
        /* https://stackoverflow.com/questions/1186414/whats-the-algorithm-to-calculate-aspect-ratio-i-need-an-output-like-43-169 */
        return (b == 0) ? a : gcd(b, a % b);
    }
}


function aspect_ratio(val, lim) {

    var lower = [0, 1];
    var upper = [1, 0];

    while (true) {
        var mediant = [lower[0] + upper[0], lower[1] + upper[1]];

        if (val * mediant[1] > mediant[0]) {
            if (lim < mediant[1]) {
                return upper;
            }
            lower = mediant;
        } else if (val * mediant[1] == mediant[0]) {
            if (lim >= mediant[1]) {
                return mediant;
            }
            if (lower[1] < upper[1]) {
                return lower;
            }
            return upper;
        } else {
            if (lim < mediant[1]) {
                return lower;
            }
            upper = mediant;
        }
    }
}

1. Copy the code text to the clipboard
2. Open a new blank file in a plain-text editor (not in a word processor)
3. Paste the code in
4. Save as a plain text format file – .txt
5. Rename the saved file extension from .txt to .jsx
6. Install or browse to the .jsx file to run

https://prepression.blogspot.com/2017/11/downloading-and-installing-adobe-scripts.html

Or use an 'online' calculator-  Ratio Calculator - Lowest Common Denominator 

Only integers or, if not, how many digits after the comma?