diff --git a/src/plugin/calendar/index.js b/src/plugin/calendar/index.js
index d8a8b516f..6180ecf2b 100644
--- a/src/plugin/calendar/index.js
+++ b/src/plugin/calendar/index.js
@@ -12,7 +12,7 @@ export default (o, c, d) => {
   const proto = c.prototype
   proto.calendar = function (referenceTime, formats) {
     const format = formats || this.$locale().calendar || calendarFormat
-    const referenceStartOfDay = d(referenceTime || undefined).startOf('d')
+    const referenceStartOfDay = d(referenceTime === 0 ? 0 : referenceTime || undefined).startOf('d')
     const diff = this.diff(referenceStartOfDay, 'd', true)
     const sameElse = 'sameElse'
     /* eslint-disable no-nested-ternary */
@@ -30,4 +30,3 @@ export default (o, c, d) => {
     return this.format(currentFormat)
   }
 }
-