diff --git a/get-cycle-day-number.js b/get-cycle-day-number.js
index b45c4ae6fe975262b3ed0aa33ae216f887cf2e6e..e5ff21aaeaa36e69840819b1707f87d663f44280 100644
--- a/get-cycle-day-number.js
+++ b/get-cycle-day-number.js
@@ -16,7 +16,13 @@ export default function config(opts = {}) {
         return day
       })
 
-    const firstBleedingDayBeforeTargetDayIndex = withWrappedDates.findIndex(day => day.wrappedDate.isBefore(targetDate))
+    const firstBleedingDayBeforeTargetDayIndex = withWrappedDates.findIndex(day => {
+      return (
+        day.wrappedDate.isEqual(targetDate) ||
+        day.wrappedDate.isBefore(targetDate)
+      )
+    })
+
     if (firstBleedingDayBeforeTargetDayIndex < 0) return null
     const previousBleedingDays = withWrappedDates.slice(firstBleedingDayBeforeTargetDayIndex)
 
diff --git a/test/get-cycle-day.spec.js b/test/get-cycle-day.spec.js
index fa6f27a7569c62ecd494a96e223776768a69c53e..222d62e95fdf92ba56085fac0738310176cba2a9 100644
--- a/test/get-cycle-day.spec.js
+++ b/test/get-cycle-day.spec.js
@@ -78,6 +78,20 @@ describe('getCycleDay', () => {
     const result = getCycleDayNumber(targetDate)
     expect(result).to.eql(18)
   })
+
+  it('gets the correct number if the target day is the only bleeding day', () => {
+    const bleedingDays = [{
+      date: '2018-05-13',
+      bleeding: {
+        value: 2
+      }
+    }]
+
+    const targetDate = '2018-05-13'
+    const getCycleDayNumber = getCycleDayNumberModule({bleedingDaysSortedByDate: bleedingDays})
+    const result = getCycleDayNumber(targetDate)
+    expect(result).to.eql(1)
+  })
 })
 
 describe('getCycleDay returns null', () => {