diff --git a/.jules/bolt.md b/.jules/bolt.md
index 3f1dfa4..0e2e314 100644
--- a/.jules/bolt.md
+++ b/.jules/bolt.md
@@ -7,3 +7,6 @@
 ## 2024-08-02 - Debouncing and offloading state derivation in Jetpack Compose
 **Learning:** In Jetpack Compose, computing expensive operations (like filtering large lists based on user input) directly within a synchronous `remember` block blocks the main UI thread. When this happens on every keystroke in a `TextField`, it causes significant UI stutter and input lag.
 **Action:** To prevent UI stutter during expensive state derivation, debounce the input using `LaunchedEffect` with `delay` and offload the computation to a background thread using `withContext(Dispatchers.Default)`. This keeps the main thread responsive for typing and animations.
+## 2024-08-04 - Code Health Improvement: Use Android's built-in file size formatter
+**Learning:** For file size formatting in Android, use `android.text.format.Formatter.formatShortFileSize` or `android.text.format.Formatter.formatFileSize` instead of writing a custom byte conversion function. It's safer, more idiomatic, correctly respects the locale, and reduces boilerplate code.
+**Action:** When working with file sizes in a Compose/Android context, default to using the Android framework's built-in `Formatter` utilities instead of custom implementations.
diff --git a/app/src/main/java/com/rockmusic/app/presentation/FolderManagerScreen.kt b/app/src/main/java/com/rockmusic/app/presentation/FolderManagerScreen.kt
index 54db53f..41fe0b2 100644
--- a/app/src/main/java/com/rockmusic/app/presentation/FolderManagerScreen.kt
+++ b/app/src/main/java/com/rockmusic/app/presentation/FolderManagerScreen.kt
@@ -7,6 +7,7 @@ import android.net.Uri
 import android.os.Build
 import android.provider.Settings
 import androidx.activity.compose.BackHandler
+import android.text.format.Formatter
 import androidx.activity.compose.rememberLauncherForActivityResult
 import androidx.activity.result.contract.ActivityResultContracts
 import androidx.compose.foundation.layout.Arrangement
@@ -317,6 +318,7 @@ private fun FolderRow(
     enabled: Boolean,
     onIncludedChange: (Boolean) -> Unit,
 ) {
+    val context = LocalContext.current
     Surface(
         shape = RoundedCornerShape(20.dp),
         color = if (included) {
@@ -347,7 +349,7 @@ private fun FolderRow(
                     overflow = TextOverflow.Ellipsis,
                 )
                 Text(
-                    "${folder.songCount} song${if (folder.songCount == 1) "" else "s"} · ${formatBytes(folder.totalBytes)}",
+                    "${folder.songCount} song${if (folder.songCount == 1) "" else "s"} · ${Formatter.formatShortFileSize(context, folder.totalBytes)}",
                     style = MaterialTheme.typography.bodySmall,
                     color = MaterialTheme.colorScheme.onSurfaceVariant,
                 )
@@ -362,14 +364,3 @@ private fun FolderRow(
     }
 }
 
-private fun formatBytes(bytes: Long): String {
-    if (bytes < 1_024L) return "$bytes B"
-    val units = arrayOf("KB", "MB", "GB", "TB")
-    var value = bytes.toDouble()
-    var unitIndex = -1
-    while (value >= 1_024.0 && unitIndex < units.lastIndex) {
-        value /= 1_024.0
-        unitIndex += 1
-    }
-    return String.format(Locale.getDefault(), "%.1f %s", value, units[unitIndex])
-}