diff --git a/library/ui/src/main/java/com/google/android/exoplayer2/ui/WebViewSubtitleOutput.java b/library/ui/src/main/java/com/google/android/exoplayer2/ui/WebViewSubtitleOutput.java
index da07eefec2..c57845da49 100644
--- a/library/ui/src/main/java/com/google/android/exoplayer2/ui/WebViewSubtitleOutput.java
+++ b/library/ui/src/main/java/com/google/android/exoplayer2/ui/WebViewSubtitleOutput.java
@@ -175,7 +175,7 @@ import java.util.Map;
                 + "right:0;"
                 + "color:%s;"
                 + "font-size:%s;"
-                + "line-height:%.2fem;"
+                + "line-height:%.2f;"
                 + "text-shadow:%s;"
                 + "'>",
             HtmlUtils.toCssRgba(style.foregroundColor),