diff --git a/src/datetime/seconds_to_duration.ts b/src/datetime/seconds_to_duration.ts
index bb74f1f..1d076a8 100644
--- a/src/datetime/seconds_to_duration.ts
+++ b/src/datetime/seconds_to_duration.ts
@@ -1,18 +1,26 @@
 const leftPad = (num: number) => (num < 10 ? `0${num}` : num);
 
-export function secondsToDuration(d: number) {
-  const h = Math.floor(d / 3600);
-  const m = Math.floor((d % 3600) / 60);
-  const s = Math.floor((d % 3600) % 60);
+export function secondsToDuration(duration: number) {
+  if (duration < 1) return null;
+  let adjDuration = duration;
+  const d = Math.floor(adjDuration / 86400);
+  adjDuration -= d*86400;
+  const h = Math.floor(adjDuration / 3600);
+  adjDuration -= h*3600;
+  const m = Math.floor(adjDuration / 60);
+  adjDuration -= m*60;
+  const s = Math.floor(adjDuration);
 
-  if (h > 0) {
-    return `${h}:${leftPad(m)}:${leftPad(s)}`;
+  // Constructing string from seconds upwards
+  let string = "" + leftPad(s);
+  if (duration >= 60) {
+    string = `${leftPad(m)}:` + string
+    if (duration >= 3600) {
+      string = `${leftPad(h)}:` + string
+      if (duration >= 86400) {
+        string = `${leftPad(d)}:` + string
+      }
+    }
   }
-  if (m > 0) {
-    return `${m}:${leftPad(s)}`;
-  }
-  if (s > 0) {
-    return "" + s;
-  }
-  return null;
+  return string;
 }