diff --git a/docs/assets/js/index.js b/docs/assets/js/index.js
index 48785f0a..a63c86c1 100644
--- a/docs/assets/js/index.js
+++ b/docs/assets/js/index.js
@@ -39,7 +39,10 @@ let typeChartArgs = {
 
 	tooltipOptions: {
 		formatTooltipX: d => (d + '').toUpperCase(),
-		formatTooltipY: d => d + ' pts',
+		formatTooltipY: (d, i) => {
+			const suffix = (i === 0) ? ' pts' : (i === 1) ? ' $' : ' %';
+			return d + suffix;
+		},
 	}
 };
 
diff --git a/docs/index.html b/docs/index.html
index 1f5ba76c..2f236a92 100644
--- a/docs/index.html
+++ b/docs/index.html
@@ -71,7 +71,10 @@ <h6>Create a chart</h6>
 
     tooltipOptions: {
       formatTooltipX: d => (d + '').toUpperCase(),
-      formatTooltipY: d => d + ' pts',
+      formatTooltipY: (d, i) => {
+        const suffix = (i === 0) ? ' pts' : (i === 1) ? ' $' : ' %';
+        return d + suffix;
+      },
     }
   });
 
diff --git a/src/js/charts/AxisChart.js b/src/js/charts/AxisChart.js
index 9c06bbd2..2f3bf0f1 100644
--- a/src/js/charts/AxisChart.js
+++ b/src/js/charts/AxisChart.js
@@ -369,7 +369,7 @@ export default class AxisChart extends BaseChart {
 					value: value,
 					yPos: set.yPositions[index],
 					color: this.colors[i],
-					formatted: formatY ? formatY(value) : value,
+					formatted: formatY ? formatY(value, i) : value,
 				};
 			});