diff --git a/src/ML-SNAP/compute_grid.cpp b/src/ML-SNAP/compute_grid.cpp
index 7a5ffe1e24..bedd8a04f4 100644
--- a/src/ML-SNAP/compute_grid.cpp
+++ b/src/ML-SNAP/compute_grid.cpp
@@ -235,8 +235,8 @@ void ComputeGrid::set_grid_local()
 
 double ComputeGrid::memory_usage()
 {
-  double nbytes = size_array_rows * size_array_cols * sizeof(double);    // grid
-  nbytes += size_array_rows * size_array_cols * sizeof(double);          // gridall
-  nbytes += size_array_cols * ngridlocal * sizeof(double);               // gridlocal
+  double nbytes = (double) size_array_rows * size_array_cols * sizeof(double);    // grid
+  nbytes += (double) size_array_rows * size_array_cols * sizeof(double);          // gridall
+  nbytes += (double) size_array_cols * ngridlocal * sizeof(double);               // gridlocal
   return nbytes;
 }
diff --git a/src/ML-SNAP/compute_grid_local.cpp b/src/ML-SNAP/compute_grid_local.cpp
index 48714962ac..0fa9440a02 100644
--- a/src/ML-SNAP/compute_grid_local.cpp
+++ b/src/ML-SNAP/compute_grid_local.cpp
@@ -265,6 +265,6 @@ void ComputeGridLocal::assign_coords()
 
 double ComputeGridLocal::memory_usage()
 {
-  int nbytes = size_local_rows * size_local_cols * sizeof(double);    // gridlocal
+  double nbytes = (double) size_local_rows * size_local_cols * sizeof(double);    // gridlocal
   return nbytes;
 }
diff --git a/src/ML-SNAP/compute_sna_grid.cpp b/src/ML-SNAP/compute_sna_grid.cpp
index 497390f99a..dbce35ae08 100644
--- a/src/ML-SNAP/compute_sna_grid.cpp
+++ b/src/ML-SNAP/compute_sna_grid.cpp
@@ -292,7 +292,7 @@ void ComputeSNAGrid::compute_array()
         }
       }
 
-  memset(&grid[0][0], 0, size_array_rows * size_array_cols * sizeof(double));
+  memset(&grid[0][0], 0, sizeof(double) * size_array_rows * size_array_cols);
 
   for (int iz = nzlo; iz <= nzhi; iz++)
     for (int iy = nylo; iy <= nyhi; iy++)
diff --git a/src/fix_store.cpp b/src/fix_store.cpp
index a80c9b0b56..b94f573376 100644
--- a/src/fix_store.cpp
+++ b/src/fix_store.cpp
@@ -77,7 +77,7 @@ vstore(nullptr), astore(nullptr), rbuf(nullptr)
     else if (narg == 6) arrayflag = 1;
     else tensorflag = 1;
     nvalues = n2*n3;
-    nbytes = n2*n3 * sizeof(double);
+    nbytes = nvalues * sizeof(double);
   }
 
   vstore = nullptr;
@@ -194,7 +194,7 @@ void FixStore::write_restart(FILE *fp)
   rbuf[0] = n1;
   rbuf[1] = n2;
   if (vecflag) memcpy(&rbuf[2],vstore,n1*sizeof(double));
-  else if (arrayflag) memcpy(&rbuf[2],&astore[0][0],n1*n2*sizeof(double));
+  else if (arrayflag) memcpy(&rbuf[2],&astore[0][0],sizeof(double)*n1*n2);
 
   int n = n1*n2 + 2;
   if (comm->me == 0) {
@@ -391,8 +391,8 @@ int FixStore::size_restart(int /*nlocal*/)
 
 double FixStore::memory_usage()
 {
-  double bytes = 0.0;
-  if (flavor == GLOBAL) bytes += n1*n2 * sizeof(double);
-  if (flavor == PERATOM) bytes += atom->nmax*n2*n3 * sizeof(double);
+  double bytes = (double) n1 * n2;
+  if (flavor == GLOBAL) bytes *= sizeof(double);
+  if (flavor == PERATOM) bytes *= atom->nmax * sizeof(double);
   return bytes;
 }