diff --git a/app/src/main/java/io/legado/app/ui/widget/page/TextChapter.kt b/app/src/main/java/io/legado/app/ui/widget/page/TextChapter.kt
index fdb9e4e2b..d9c57c4ce 100644
--- a/app/src/main/java/io/legado/app/ui/widget/page/TextChapter.kt
+++ b/app/src/main/java/io/legado/app/ui/widget/page/TextChapter.kt
@@ -54,8 +54,8 @@ data class TextChapter(
 
     fun getReadLength(pageIndex: Int): Int {
         var length = 0
-        val maxIndex = min(pageIndex, pageLines.lastIndex)
-        for (index in 0..maxIndex) {
+        val maxIndex = min(pageIndex, pageLines.size)
+        for (index in 0 until maxIndex) {
             length += pageLengths[index]
         }
         return length