diff --git a/base/serial/impl/psb_c_csr_impl.f90 b/base/serial/impl/psb_c_csr_impl.f90
index 1fda1ab9..6885be6a 100644
--- a/base/serial/impl/psb_c_csr_impl.f90
+++ b/base/serial/impl/psb_c_csr_impl.f90
@@ -3391,8 +3391,8 @@ subroutine psb_ccsrspspmm(a,b,c,info)
   ma = max(na,1)
   mb = max(mb,1)
   nb = max(nb,1)
-  nze = ma*(((nza+ma-1)/ma)*((nzb+mb-1)/mb) )
-  nzeb = (((nza+na-1)/na)*((nzb+nb-1)/nb))*nb
+  nze = max(1,ma*(((nza+ma-1)/ma)*((nzb+mb-1)/mb) ))
+  nzeb = max(1,(((nza+na-1)/na)*((nzb+nb-1)/nb))*nb)
   nzc = min(nzc, nze+nzeb)
   call c%allocate(ma,nb,nzc)
 
diff --git a/base/serial/impl/psb_d_csr_impl.f90 b/base/serial/impl/psb_d_csr_impl.f90
index fe62c86c..f1f496a6 100644
--- a/base/serial/impl/psb_d_csr_impl.f90
+++ b/base/serial/impl/psb_d_csr_impl.f90
@@ -3391,8 +3391,8 @@ subroutine psb_dcsrspspmm(a,b,c,info)
   ma = max(na,1)
   mb = max(mb,1)
   nb = max(nb,1)
-  nze = ma*(((nza+ma-1)/ma)*((nzb+mb-1)/mb) )
-  nzeb = (((nza+na-1)/na)*((nzb+nb-1)/nb))*nb
+  nze = max(1,ma*(((nza+ma-1)/ma)*((nzb+mb-1)/mb) ))
+  nzeb = max(1,(((nza+na-1)/na)*((nzb+nb-1)/nb))*nb)
   nzc = min(nzc, nze+nzeb)
   call c%allocate(ma,nb,nzc)
 
diff --git a/base/serial/impl/psb_s_csr_impl.f90 b/base/serial/impl/psb_s_csr_impl.f90
index 1e035662..b283d93f 100644
--- a/base/serial/impl/psb_s_csr_impl.f90
+++ b/base/serial/impl/psb_s_csr_impl.f90
@@ -3391,8 +3391,8 @@ subroutine psb_scsrspspmm(a,b,c,info)
   ma = max(na,1)
   mb = max(mb,1)
   nb = max(nb,1)
-  nze = ma*(((nza+ma-1)/ma)*((nzb+mb-1)/mb) )
-  nzeb = (((nza+na-1)/na)*((nzb+nb-1)/nb))*nb
+  nze = max(1,ma*(((nza+ma-1)/ma)*((nzb+mb-1)/mb) ))
+  nzeb = max(1,(((nza+na-1)/na)*((nzb+nb-1)/nb))*nb)
   nzc = min(nzc, nze+nzeb)
   call c%allocate(ma,nb,nzc)
 
diff --git a/base/serial/impl/psb_z_csr_impl.f90 b/base/serial/impl/psb_z_csr_impl.f90
index 21f82bf9..a1849c8e 100644
--- a/base/serial/impl/psb_z_csr_impl.f90
+++ b/base/serial/impl/psb_z_csr_impl.f90
@@ -3391,8 +3391,8 @@ subroutine psb_zcsrspspmm(a,b,c,info)
   ma = max(na,1)
   mb = max(mb,1)
   nb = max(nb,1)
-  nze = ma*(((nza+ma-1)/ma)*((nzb+mb-1)/mb) )
-  nzeb = (((nza+na-1)/na)*((nzb+nb-1)/nb))*nb
+  nze = max(1,ma*(((nza+ma-1)/ma)*((nzb+mb-1)/mb) ))
+  nzeb = max(1,(((nza+na-1)/na)*((nzb+nb-1)/nb))*nb)
   nzc = min(nzc, nze+nzeb)
   call c%allocate(ma,nb,nzc)