diff --git a/src/arc.js b/src/arc.js
index fa31784..5abcdde 100644
--- a/src/arc.js
+++ b/src/arc.js
@@ -94,7 +94,9 @@ c3_chart_internal_fn.transformForArcLabel = function (d) {
         x = isNaN(c[0]) ? 0 : c[0];
         y = isNaN(c[1]) ? 0 : c[1];
         h = Math.sqrt(x * x + y * y);
-        if (config.pie_label_ratio) {
+        if ($$.hasType('donut') && config.donut_label_ratio) {
+            ratio = isFunction(config.donut_label_ratio) ? config.donut_label_ratio(d, $$.radius, h) : config.donut_label_ratio;
+        } else if ($$.hasType('pie') && config.pie_label_ratio) {
             ratio = isFunction(config.pie_label_ratio) ? config.pie_label_ratio(d, $$.radius, h) : config.pie_label_ratio;
         } else {
             ratio = $$.radius && h ? (36 / $$.radius > 0.375 ? 1.175 - 36 / $$.radius : 0.8) * $$.radius / h : 0;
diff --git a/src/config.js b/src/config.js
index 1e3f19b..240e394 100644
--- a/src/config.js
+++ b/src/config.js
@@ -190,6 +190,7 @@ c3_chart_internal_fn.getDefaultConfig = function () {
         donut_label_show: true,
         donut_label_format: undefined,
         donut_label_threshold: 0.05,
+        donut_label_ratio: undefined,
         donut_width: undefined,
         donut_title: "",
         donut_expand: {},