diff --git a/src/plugins/imageformats/wbmp/qwbmphandler.cpp b/src/plugins/imageformats/wbmp/qwbmphandler.cpp
index 0d08422d35b636221edae80f868e078567a41077..5fe8ec9eb61c20125bfe0f63ab406353e21c254e 100644
--- a/src/plugins/imageformats/wbmp/qwbmphandler.cpp
+++ b/src/plugins/imageformats/wbmp/qwbmphandler.cpp
@@ -244,7 +244,7 @@ bool WBMPReader::canRead(QIODevice *device)
         WBMPHeader hdr;
         if (readWBMPHeader(device, &hdr)) {
             if ((hdr.type == 0) && (hdr.format == 0)) {
-                qint64 imageSize = hdr.height * ((hdr.width + 7) / 8);
+                const qint64 imageSize = hdr.height * ((qint64(hdr.width) + 7) / 8);
                 qint64 available = device->bytesAvailable();
                 device->seek(oldPos);
                 return (imageSize == available);