diff --git a/docs/index.html b/docs/index.html
index 7b80e0f..7ca9b8f 100644
--- a/docs/index.html
+++ b/docs/index.html
@@ -30,6 +30,8 @@ <h3>Graph Shape/Bounds</h3>
             <label for="dp_max">Maximum Dry Bulb (&deg;C/&deg;F)</label><br>
             <input type="number" id="alt" step="10" value="0">
             <label for="alt">Altitude (m/ft)</label><br>
+            <input type="checkbox" id="flip">
+            <label for="flip">Flip X and Y to render a Mollier Diagram</label><br>
             <input type="checkbox" id="adv">
             <label for="adv">Advanced mode: Additionally calculate humidity ratio, vapor pressure, enthalpy, and
                 specific volume. (Psychart calculates dry bulb, wet bulb, dew point, and relative humidity by
diff --git a/src/app.ts b/src/app.ts
index 9a1cb8c..e71fd4c 100644
--- a/src/app.ts
+++ b/src/app.ts
@@ -78,7 +78,7 @@ setOnClick('btnGenerate', () => {
                 dbMax: dbMax,
                 dbMin: dbMin,
                 dpMax: dpMax,
-                flipXY: false, // TODO - add control for flipping XY in standalone app
+                flipXY: getCheckedState('flip'),
                 regions: Psychart.getRegionNamesAndTips().map(([name,]) => name).filter(name => getCheckedState(name)),
                 series: {
                     0: {