diff --git a/android/app/src/main/java/com/fabledsword/minstrel/library/data/LibraryMappers.kt b/android/app/src/main/java/com/fabledsword/minstrel/library/data/LibraryMappers.kt
index 4c3c214a..a6cf3982 100644
--- a/android/app/src/main/java/com/fabledsword/minstrel/library/data/LibraryMappers.kt
+++ b/android/app/src/main/java/com/fabledsword/minstrel/library/data/LibraryMappers.kt
@@ -11,6 +11,8 @@ import com.fabledsword.minstrel.models.wire.AlbumWire
 import com.fabledsword.minstrel.models.wire.ArtistDetailWire
 import com.fabledsword.minstrel.models.wire.ArtistWire
 import com.fabledsword.minstrel.models.wire.TrackWire
+import com.fabledsword.minstrel.shared.millisToSeconds
+import com.fabledsword.minstrel.shared.secondsToMillis
 
 // Wire to Entity — used after a successful sync/fetch to persist into Room.
 // Entity fields are a subset of wire fields (display names + sort keys);
@@ -37,7 +39,7 @@ fun TrackWire.toEntity(): CachedTrackEntity =
         albumId = albumId,
         artistId = artistId,
         title = title,
-        durationMs = durationSec * MILLIS_PER_SECOND,
+        durationMs = durationSec.secondsToMillis(),
         trackNumber = trackNumber,
         discNumber = discNumber,
     )
@@ -94,7 +96,7 @@ fun CachedTrackEntity.toDomain(
         artistName = artistName,
         trackNumber = trackNumber,
         discNumber = discNumber,
-        durationSec = durationMs / MILLIS_PER_SECOND,
+        durationSec = durationMs.millisToSeconds(),
     )
 
 // Wire to Domain — for fresh server responses that bypass the cache
@@ -136,5 +138,3 @@ fun AlbumWire.toDomain(): AlbumRef =
         durationSec = durationSec,
         coverUrl = coverUrl,
     )
-
-private const val MILLIS_PER_SECOND = 1000
diff --git a/android/app/src/main/java/com/fabledsword/minstrel/library/ui/AlbumDetailScreen.kt b/android/app/src/main/java/com/fabledsword/minstrel/library/ui/AlbumDetailScreen.kt
index 7fcaf2c9..02bab424 100644
--- a/android/app/src/main/java/com/fabledsword/minstrel/library/ui/AlbumDetailScreen.kt
+++ b/android/app/src/main/java/com/fabledsword/minstrel/library/ui/AlbumDetailScreen.kt
@@ -55,6 +55,7 @@ import com.fabledsword.minstrel.models.AlbumRef
 import com.fabledsword.minstrel.models.TrackRef
 import com.fabledsword.minstrel.nav.AlbumDetail
 import com.fabledsword.minstrel.nav.ArtistDetail
+import com.fabledsword.minstrel.shared.formatDuration
 import com.fabledsword.minstrel.shared.widgets.CachedDot
 import com.fabledsword.minstrel.shared.widgets.EmptyState
 import com.fabledsword.minstrel.shared.widgets.LikeButton
@@ -352,7 +353,7 @@ private fun TrackRow(
         }
         CachedDot(track.id)
         Text(
-            text = formatDuration(track.durationSec),
+            text = formatDuration(track.durationSec, zero = "--:--"),
             style = MaterialTheme.typography.bodySmall,
             color = MaterialTheme.colorScheme.onSurfaceVariant,
             modifier = Modifier.padding(start = 12.dp),
@@ -421,12 +422,3 @@ private fun SeededAlbumLoading(seed: AlbumRef) {
         items(SKELETON_TRACK_ROWS) { SkeletonTrackRow() }
     }
 }
-
-private const val SECONDS_PER_MINUTE = 60
-
-private fun formatDuration(seconds: Int): String {
-    if (seconds <= 0) return "--:--"
-    val m = seconds / SECONDS_PER_MINUTE
-    val s = seconds % SECONDS_PER_MINUTE
-    return "$m:${s.toString().padStart(2, '0')}"
-}
diff --git a/android/app/src/main/java/com/fabledsword/minstrel/player/ui/NowPlayingScreen.kt b/android/app/src/main/java/com/fabledsword/minstrel/player/ui/NowPlayingScreen.kt
index 3a770dfc..af6bef5c 100644
--- a/android/app/src/main/java/com/fabledsword/minstrel/player/ui/NowPlayingScreen.kt
+++ b/android/app/src/main/java/com/fabledsword/minstrel/player/ui/NowPlayingScreen.kt
@@ -69,6 +69,8 @@ import com.fabledsword.minstrel.nav.LocalAnimatedContentScope
 import com.fabledsword.minstrel.nav.LocalSharedTransitionScope
 import com.fabledsword.minstrel.nav.NowPlaying
 import com.fabledsword.minstrel.nav.Queue
+import com.fabledsword.minstrel.shared.formatDuration
+import com.fabledsword.minstrel.shared.millisToSeconds
 import com.fabledsword.minstrel.shared.widgets.LikeButton
 import com.fabledsword.minstrel.shared.widgets.trackactions.TrackActionsButton
 import com.fabledsword.minstrel.shared.widgets.trackactions.TrackActionsViewModel
@@ -78,8 +80,6 @@ import com.fabledsword.minstrel.theme.LocalActionColors
 private const val COVER_MAX_WIDTH_DP = 320
 private const val TRANSPORT_ICON_DP = 36
 private const val PLAY_PAUSE_ICON_DP = 56
-private const val MS_PER_SECOND = 1000L
-private const val SECONDS_PER_MINUTE = 60L
 private const val POP_GRACE_MS = 500L
 
 // Vertical drag-down threshold (in pixels) past which the gesture
@@ -420,12 +420,12 @@ private fun ScrubberRow(positionMs: Long, durationMs: Long, onSeek: (Long) -> Un
         horizontalArrangement = Arrangement.SpaceBetween,
     ) {
         Text(
-            text = formatMillis(positionMs),
+            text = formatDuration(positionMs.millisToSeconds()),
             style = MaterialTheme.typography.labelSmall,
             color = MaterialTheme.colorScheme.onSurfaceVariant,
         )
         Text(
-            text = formatMillis(durationMs),
+            text = formatDuration(durationMs.millisToSeconds()),
             style = MaterialTheme.typography.labelSmall,
             color = MaterialTheme.colorScheme.onSurfaceVariant,
         )
@@ -471,11 +471,3 @@ private fun TransportRow(
         }
     }
 }
-
-private fun formatMillis(ms: Long): String {
-    if (ms <= 0) return "0:00"
-    val totalSeconds = ms / MS_PER_SECOND
-    val minutes = totalSeconds / SECONDS_PER_MINUTE
-    val seconds = totalSeconds % SECONDS_PER_MINUTE
-    return "%d:%02d".format(minutes, seconds)
-}
diff --git a/android/app/src/main/java/com/fabledsword/minstrel/player/ui/QueueScreen.kt b/android/app/src/main/java/com/fabledsword/minstrel/player/ui/QueueScreen.kt
index 04ab26e3..71e2f64d 100644
--- a/android/app/src/main/java/com/fabledsword/minstrel/player/ui/QueueScreen.kt
+++ b/android/app/src/main/java/com/fabledsword/minstrel/player/ui/QueueScreen.kt
@@ -34,6 +34,7 @@ import com.composables.icons.lucide.ArrowLeft
 import com.composables.icons.lucide.Lucide
 import com.composables.icons.lucide.Volume2
 import com.fabledsword.minstrel.models.TrackRef
+import com.fabledsword.minstrel.shared.formatDuration
 import com.fabledsword.minstrel.shared.widgets.EmptyState
 
 @OptIn(ExperimentalMaterial3Api::class)
@@ -149,12 +150,4 @@ private fun queueSubtitle(track: TrackRef): String = listOf(track.artistName, tr
     .filter { it.isNotEmpty() }
     .joinToString(" · ")
 
-private const val SECONDS_PER_MINUTE = 60
-
-private fun formatDuration(seconds: Int): String {
-    val mins = seconds / SECONDS_PER_MINUTE
-    val secs = seconds % SECONDS_PER_MINUTE
-    return "%d:%02d".format(mins, secs)
-}
-
 private const val HIGHLIGHT_ALPHA = 0.12f
diff --git a/android/app/src/main/java/com/fabledsword/minstrel/playlists/ui/PlaylistDetailScreen.kt b/android/app/src/main/java/com/fabledsword/minstrel/playlists/ui/PlaylistDetailScreen.kt
index d9033345..83000c9f 100644
--- a/android/app/src/main/java/com/fabledsword/minstrel/playlists/ui/PlaylistDetailScreen.kt
+++ b/android/app/src/main/java/com/fabledsword/minstrel/playlists/ui/PlaylistDetailScreen.kt
@@ -72,6 +72,7 @@ import com.fabledsword.minstrel.player.PlayerController
 import com.fabledsword.minstrel.likes.data.LikesRepository
 import com.fabledsword.minstrel.playlists.data.PlaylistDetailRef
 import com.fabledsword.minstrel.playlists.data.PlaylistsRepository
+import com.fabledsword.minstrel.shared.formatDuration
 import com.fabledsword.minstrel.shared.widgets.CachedDot
 import com.fabledsword.minstrel.shared.widgets.LikeButton
 import com.fabledsword.minstrel.shared.widgets.PullToRefreshScaffold
@@ -531,7 +532,7 @@ private fun TrackRow(
         }
         row.trackId?.let { CachedDot(it) }
         Text(
-            text = formatDuration(row.durationSec),
+            text = formatDuration(row.durationSec, zero = "--:--"),
             style = MaterialTheme.typography.bodySmall,
             color = MaterialTheme.colorScheme.onSurfaceVariant.copy(alpha = rowAlpha),
             modifier = Modifier.padding(start = 12.dp),
@@ -632,16 +633,8 @@ private fun ErrorBlock(message: String, onRetry: () -> Unit) {
 
 // ─── Helpers ─────────────────────────────────────────────────────────
 
-private const val SECONDS_PER_MINUTE = 60
 private const val UNAVAILABLE_ALPHA = 0.4f
 
-private fun formatDuration(seconds: Int): String {
-    if (seconds <= 0) return "--:--"
-    val m = seconds / SECONDS_PER_MINUTE
-    val s = seconds % SECONDS_PER_MINUTE
-    return "$m:${s.toString().padStart(2, '0')}"
-}
-
 /**
  * Lossy mapping: PlaylistTrackRef → TrackRef so the player can take it.
  * Caller must filter `isAvailable && streamUrl != null` first.
diff --git a/android/app/src/main/java/com/fabledsword/minstrel/quarantine/data/QuarantineRepository.kt b/android/app/src/main/java/com/fabledsword/minstrel/quarantine/data/QuarantineRepository.kt
index d8d4ac80..f67b0d28 100644
--- a/android/app/src/main/java/com/fabledsword/minstrel/quarantine/data/QuarantineRepository.kt
+++ b/android/app/src/main/java/com/fabledsword/minstrel/quarantine/data/QuarantineRepository.kt
@@ -8,6 +8,7 @@ import com.fabledsword.minstrel.cache.mutations.MutationQueue
 import com.fabledsword.minstrel.models.QuarantineRef
 import com.fabledsword.minstrel.models.TrackRef
 import com.fabledsword.minstrel.models.wire.QuarantineMineWire
+import com.fabledsword.minstrel.shared.secondsToMillis
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.map
 import kotlinx.datetime.Clock
@@ -16,8 +17,6 @@ import retrofit2.create
 import javax.inject.Inject
 import javax.inject.Singleton
 
-private const val MS_PER_SECOND = 1000
-
 /**
  * Outcome of an `unflag` call — mirrors LikesRepository.toggleLike's
  * RequestOutcome flavor. ACCEPTED = server confirmed; QUEUED = the
@@ -142,7 +141,7 @@ private fun TrackRef.toQuarantineEntity(reason: String, notes: String): CachedQu
         notes = notes.ifEmpty { null },
         createdAt = Clock.System.now().toString(),
         trackTitle = title,
-        trackDurationMs = durationSec * MS_PER_SECOND,
+        trackDurationMs = durationSec.secondsToMillis(),
         albumId = albumId,
         albumTitle = albumTitle,
         albumCoverArtPath = null,