diff --git a/CHANGELOG.md b/CHANGELOG.md
index e0abf84d..4fe3d828 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -28,6 +28,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
 - (**Browse**) Merge languages filter of the sources and extensions into one
 - (**Search**) Hide "pinned" sources button in global search in case no sources are pinned
 - (**Extensions**) Show "obsolete" information more discretely with the "uninstall" action instead of grouping obsolete extensions at the top of the page
+- (**Migration**) Mark all chapters as read up to the highest read chapter number. Previously matching chapter numbers got marked as read. E.g., Read up to chapter 250. The destination has a chapter 249.5 but the original source does not. Chapter 249.5 did not get marked as read.
 
 ### Fixed
 
diff --git a/src/features/migration/MangaMigration.ts b/src/features/migration/MangaMigration.ts
index 4fb786c9..4a50fa88 100644
--- a/src/features/migration/MangaMigration.ts
+++ b/src/features/migration/MangaMigration.ts
@@ -138,18 +138,27 @@ export class MangaMigration {
         const chaptersToMigrateTo = mangaToMigrateToInfo.fetchChapters?.chapters;
         const migratableChapters = Chapters.getMatchingChapterNumberChapters(chaptersToMigrate, chaptersToMigrateTo);
 
-        const readChapters: number[] = [];
+        const highestReadChapterNumber = chaptersToMigrate.reduce((chapterNumber, chapterToMigrate) => {
+            if (chapterToMigrate.isRead && chapterNumber < chapterToMigrate.chapterNumber) {
+                return chapterToMigrate.chapterNumber;
+            }
+
+            return chapterNumber;
+        }, Number.MIN_SAFE_INTEGER);
+
         const bookmarkedChapters: number[] = [];
 
         const chapterPreDeleteIds: number[] = [];
         const chapterUpdateItems: SetChapterMetasItemInput[] = [];
 
-        migratableChapters.forEach(([chapterToMigrate, chapterToMigrateTo]) => {
-            const { isRead, isBookmarked, meta } = chapterToMigrate;
+        const readChapters = Chapters.getIds(
+            chaptersToMigrateTo.filter(
+                (chapterToMigrateTo) => chapterToMigrateTo.chapterNumber <= highestReadChapterNumber,
+            ),
+        );
 
-            if (isRead) {
-                readChapters.push(chapterToMigrateTo.id);
-            }
+        migratableChapters.forEach(([chapterToMigrate, chapterToMigrateTo]) => {
+            const { isBookmarked, meta } = chapterToMigrate;
 
             if (isBookmarked) {
                 bookmarkedChapters.push(chapterToMigrateTo.id);