diff --git a/maxutils/maxbase/src/format.cc b/maxutils/maxbase/src/format.cc
index 8ef1bb28f..b8562ea16 100644
--- a/maxutils/maxbase/src/format.cc
+++ b/maxutils/maxbase/src/format.cc
@@ -59,7 +59,7 @@ namespace maxbase
 std::string to_binary_size(int64_t size)
 {
     // Calculate log1024(size) and round it up
-    int idx = ceil(log(size) / log(1024));
+    int idx = floor(log(size) / log(1024));
     double num = size / pow(1024, idx);
     char buf[200];      // Enough for all possible values
     snprintf(buf, sizeof(buf), "%.2lf%s", num, get_binary_size_suffix(idx));
diff --git a/server/core/query_classifier.cc b/server/core/query_classifier.cc
index 8adaaaf7c..c53c5058f 100644
--- a/server/core/query_classifier.cc
+++ b/server/core/query_classifier.cc
@@ -19,6 +19,7 @@
 #include <unordered_map>
 #include <maxscale/alloc.h>
 #include <maxbase/atomic.h>
+#include <maxbase/format.hh>
 #include <maxscale/config.h>
 #include <maxscale/json_api.h>
 #include <maxscale/log.h>
@@ -396,9 +397,9 @@ bool qc_setup(const QC_CACHE_PROPERTIES* cache_properties,
 
             if (cache_max_size)
             {
-                MXS_NOTICE("Query classification results are cached and reused, "
-                           "cache max size: %" PRIi64 "",
-                           cache_max_size);
+                MXS_NOTICE("Query classification results are cached and reused. "
+                           "Memory used per thread: %s",
+                           mxb::to_binary_size(cache_max_size).c_str());
             }
             else
             {