diff --git a/src/java/org/apache/cassandra/io/sstable/SSTableReader.java b/src/java/org/apache/cassandra/io/sstable/SSTableReader.java
index e30e4171a2..31a40cb4bc 100644
--- a/src/java/org/apache/cassandra/io/sstable/SSTableReader.java
+++ b/src/java/org/apache/cassandra/io/sstable/SSTableReader.java
@@ -594,7 +594,7 @@ public class SSTableReader extends SSTable
      */
     public long estimatedKeys()
     {
-        return indexSummary.size() * indexSummary.getIndexInterval();
+        return ((long) indexSummary.size()) * indexSummary.getIndexInterval();
     }
 
     /**