diff --git a/src/fix_shear_history.cpp b/src/fix_shear_history.cpp
index f562508efa..bebd23386d 100644
--- a/src/fix_shear_history.cpp
+++ b/src/fix_shear_history.cpp
@@ -283,8 +283,8 @@ double FixShearHistory::memory_usage()
 {
   int nmax = atom->nmax;
   double bytes = nmax * sizeof(int);
-  bytes = nmax * sizeof(int *);
-  bytes = nmax * sizeof(double *);
+  bytes += nmax * sizeof(int *);
+  bytes += nmax * sizeof(double *);
 
   int nmypage = comm->nthreads;
   for (int i = 0; i < nmypage; i++) {