diff --git a/src/EXTRA-FIX/fix_ttm_grid.cpp b/src/EXTRA-FIX/fix_ttm_grid.cpp
index ff9f864f8e..ec5ba2540e 100644
--- a/src/EXTRA-FIX/fix_ttm_grid.cpp
+++ b/src/EXTRA-FIX/fix_ttm_grid.cpp
@@ -411,7 +411,6 @@ void FixTTMGrid::write_restart_file(const char *file)
     if (fpout == nullptr)
       error->one(FLERR,"Cannot open fix ttm/grid restart file {}: {}",outfile,utils::getsyserror());
 
-    bigint ngrid = (bigint) nxgrid * nygrid * nzgrid;
     fmt::print(fpout,"# DATE: {} UNITS: {} COMMENT: "
                "Electron temperature on {}x{}x{} grid at step {} - "
                "created by fix {}\n",
diff --git a/src/dump_grid.cpp b/src/dump_grid.cpp
index 7a3de98921..ded86d414d 100644
--- a/src/dump_grid.cpp
+++ b/src/dump_grid.cpp
@@ -425,7 +425,7 @@ void DumpGrid::header_binary_triclinic(bigint ndump)
 
 /* ---------------------------------------------------------------------- */
 
-void DumpGrid::header_item(bigint ndump)
+void DumpGrid::header_item(bigint /*ndump*/)
 {
   if (unit_flag && !unit_count) {
     ++unit_count;
@@ -445,7 +445,7 @@ void DumpGrid::header_item(bigint ndump)
 
 /* ---------------------------------------------------------------------- */
 
-void DumpGrid::header_item_triclinic(bigint ndump)
+void DumpGrid::header_item_triclinic(bigint /*ndump*/)
 {
   if (unit_flag && !unit_count) {
     ++unit_count;
diff --git a/src/dump_grid_vtk.cpp b/src/dump_grid_vtk.cpp
index 6a4b05d9f3..a143a04152 100644
--- a/src/dump_grid_vtk.cpp
+++ b/src/dump_grid_vtk.cpp
@@ -74,7 +74,7 @@ void DumpGridVTK::init_style()
 
 /* ---------------------------------------------------------------------- */
 
-void DumpGridVTK::write_header(bigint ndump)
+void DumpGridVTK::write_header(bigint /*ndump*/)
 {
   if (me) return;
 
diff --git a/src/dump_grid_vtk.h b/src/dump_grid_vtk.h
index ca8ffed525..4f4da3fd4e 100644
--- a/src/dump_grid_vtk.h
+++ b/src/dump_grid_vtk.h
@@ -31,7 +31,7 @@ class DumpGridVTK : public DumpGrid {
 
  protected:
   int mode;
-  double *xcoord,*ycoord,*zcoord;
+  double *xcoord, *ycoord, *zcoord;
 
   // methods
 
diff --git a/src/dump_image.cpp b/src/dump_image.cpp
index 3085843e7e..32b4a69feb 100644
--- a/src/dump_image.cpp
+++ b/src/dump_image.cpp
@@ -1372,7 +1372,7 @@ void DumpImage::grid_cell_corners_2d(int ix, int iy)
       }
 
   } else {
-    double lamda[3],xone[3];
+    double lamda[3];
     lamda[2] = 0.0;
 
     double dx = 1.0 / nxgrid;
@@ -1411,7 +1411,7 @@ void DumpImage::grid_cell_corners_3d(int ix, int iy, int iz)
         }
 
   } else {
-    double lamda[3],xone[3];
+    double lamda[3];
 
     double dx = 1.0 / nxgrid;
     double dy = 1.0 / nygrid;
diff --git a/src/fix_ave_grid.cpp b/src/fix_ave_grid.cpp
index c6040903bb..6e0e16b360 100644
--- a/src/fix_ave_grid.cpp
+++ b/src/fix_ave_grid.cpp
@@ -518,8 +518,6 @@ void FixAveGrid::setup(int /*vflag*/)
 
 void FixAveGrid::end_of_step()
 {
-  int m,ix,iy,iz;
-
   // skip if not step which requires doing something
 
   bigint ntimestep = update->ntimestep;
@@ -1524,7 +1522,7 @@ void FixAveGrid::deallocate_one_grid(GridData *grid,
    if ATOM mode, also include per-grid count
 ------------------------------------------------------------------------- */
 
-double FixAveGrid::size_grid(GridData *grid)
+double FixAveGrid::size_grid(GridData * /*grid*/)
 {
   int nper = nvalues;
   if (modeatom) nper++;
@@ -1867,8 +1865,6 @@ void FixAveGrid::unpack_reverse_grid(int /*which*/, void *vbuf, int nlist, int *
 
 void FixAveGrid::pack_remap_grid(int /*which*/, void *vbuf, int nlist, int *list)
 {
-  int i,j,m,iwindow;
-
   auto buf = (double *) vbuf;
 
   int running_flag = 0;
@@ -1876,13 +1872,13 @@ void FixAveGrid::pack_remap_grid(int /*which*/, void *vbuf, int nlist, int *list
   int window_flag = 0;
   if (aveflag == WINDOW) window_flag = 1;
 
-  m = 0;
-  for (i = 0; i < nlist; i++) {
+  int m = 0;
+  for (int i = 0; i < nlist; i++) {
     m += pack_one_grid(grid_sample_previous,list[i],&buf[m]);
     m += pack_one_grid(grid_nfreq_previous,list[i],&buf[m]);
     if (running_flag) m += pack_one_grid(grid_running_previous,list[i],&buf[m]);
     if (window_flag)
-      for (iwindow = 0; iwindow < nwindow; iwindow++)
+      for (int iwindow = 0; iwindow < nwindow; iwindow++)
         m += pack_one_grid(grid_window_previous[iwindow],list[i],&buf[m]);
   }
 }
@@ -1894,22 +1890,20 @@ void FixAveGrid::pack_remap_grid(int /*which*/, void *vbuf, int nlist, int *list
 
 void FixAveGrid::unpack_remap_grid(int /*which*/, void *vbuf, int nlist, int *list)
 {
-  int i,j,m,iwindow;
-
-  auto buf = (double *) vbuf;
+   auto buf = (double *) vbuf;
 
   int running_flag = 0;
   if (aveflag == RUNNING || aveflag == WINDOW) running_flag = 1;
   int window_flag = 0;
   if (aveflag == WINDOW) window_flag = 1;
 
-  m = 0;
-  for (i = 0; i < nlist; i++) {
+  int m = 0;
+  for (int i = 0; i < nlist; i++) {
     m += unpack_one_grid(&buf[m],grid_sample,list[i]);
     m += unpack_one_grid(&buf[m],grid_nfreq,list[i]);
     if (running_flag) m += unpack_one_grid(&buf[m],grid_running,list[i]);
     if (window_flag)
-      for (iwindow = 0; iwindow < nwindow; iwindow++)
+      for (int iwindow = 0; iwindow < nwindow; iwindow++)
         m += unpack_one_grid(&buf[m],grid_window[iwindow],list[i]);
   }
 }