diff --git a/lib/cycle.js b/lib/cycle.js
index 8fd7bd1..8de6723 100644
--- a/lib/cycle.js
+++ b/lib/cycle.js
@@ -40,7 +40,7 @@ export default function config(opts) {
     const lastMensesLocalDate = LocalDate.parse(lastMensesStart.date)
     const diffInDays = lastMensesLocalDate.until(targetDate, DAYS)
     // take maxCycleLength into account (we don't display cycle day numbers higher than 99 at the moment)
-    if (diffInDays >= 99) return null
+    if (diffInDays >= maxCycleLength) return null
     // cycle starts at day 1
     return diffInDays + 1
   }
@@ -65,7 +65,6 @@ export default function config(opts) {
   }
 
   function getCycleForCycleStartDay(startDay) {
-    // TODO this needs to be made cycle length aware. all other places can go?
     const cycleStartIndex = cycleDaysSortedByDate.indexOf(startDay)
     const i = cycleStartsSortedByDate.indexOf(startDay)
     const nextMensesStart = cycleStartsSortedByDate[i - 1]
diff --git a/test/cycle.spec.js b/test/cycle.spec.js
index 232e2bc..8c746b0 100644
--- a/test/cycle.spec.js
+++ b/test/cycle.spec.js
@@ -71,6 +71,27 @@ describe('getCycleDayNumber', () => {
     const result = getCycleDayNumber(targetDate)
     expect(result).to.be.null()
   })
+
+  it('returns null if the cycle is longer than the max', function () {
+    const cycleStarts = [{
+      date: '2018-05-09',
+      isCycleStart: true,
+      bleeding: {
+        value: 2
+      }
+    }, {
+      date: '2018-05-03',
+      isCycleStart: true,
+      bleeding: { value: 2 }
+    }]
+    // we use the default 99 days max length
+    const getCycleDayNumber = cycleModule({
+      cycleStartsSortedByDate: cycleStarts
+    }).getCycleDayNumber
+    const targetDate = '2018-08-16'
+    const result = getCycleDayNumber(targetDate)
+    expect(result).to.be.null()
+  })
 })
 
 describe('getPreviousCycle', () => {