diff --git a/raster/r.basins.fill/read_map.c b/raster/r.basins.fill/read_map.c
index 67fdf9460f1..3e68a7deb13 100644
--- a/raster/r.basins.fill/read_map.c
+++ b/raster/r.basins.fill/read_map.c
@@ -25,7 +25,7 @@ CELL *read_map(const char *name, int nomask, int nrows, int ncols)
     void (*get_row)(int, CELL *, int);
 
     /* allocate entire map */
-    map = (CELL *)G_malloc(nrows * ncols * sizeof(CELL));
+    map = (CELL *)G_malloc((size_t)nrows * ncols * sizeof(CELL));
 
     /* open the map */
     fd = Rast_open_old(name, "");
diff --git a/raster/r.distance/report.c b/raster/r.distance/report.c
index 34b68108803..f0299e6288c 100644
--- a/raster/r.distance/report.c
+++ b/raster/r.distance/report.c
@@ -76,8 +76,9 @@ void report(struct Parms *parms)
     }
 
     if (parms->sort > 0)
-        lines = (struct ReportLine *)G_malloc(
-            map1->edges.ncats * map2->edges.ncats * sizeof(struct ReportLine));
+        lines = (struct ReportLine *)G_malloc((size_t)map1->edges.ncats *
+                                              map2->edges.ncats *
+                                              sizeof(struct ReportLine));
     else
         lines = NULL;
     nlines = 0;
diff --git a/raster/r.in.mat/main.c b/raster/r.in.mat/main.c
index 24402042fe5..4023ed0648e 100644
--- a/raster/r.in.mat/main.c
+++ b/raster/r.in.mat/main.c
@@ -338,16 +338,16 @@ int main(int argc, char *argv[])
                 /*   0=double       1=float   2=32bit signed int   5=8bit
                  * unsigned int(text)   */
             case 0:
-                G_fseek(fp1, mrows * ncols * sizeof(double), SEEK_CUR);
+                G_fseek(fp1, (off_t)mrows * ncols * sizeof(double), SEEK_CUR);
                 break;
             case 1:
-                G_fseek(fp1, mrows * ncols * sizeof(float), SEEK_CUR);
+                G_fseek(fp1, (off_t)mrows * ncols * sizeof(float), SEEK_CUR);
                 break;
             case 2:
-                G_fseek(fp1, mrows * ncols * sizeof(int), SEEK_CUR);
+                G_fseek(fp1, (off_t)mrows * ncols * sizeof(int), SEEK_CUR);
                 break;
             case 5:
-                G_fseek(fp1, mrows * ncols * sizeof(char), SEEK_CUR);
+                G_fseek(fp1, (off_t)mrows * ncols * sizeof(char), SEEK_CUR);
                 break;
             default:
                 G_fatal_error("unusual array");
diff --git a/raster/r.in.xyz/main.c b/raster/r.in.xyz/main.c
index beae3386181..e0a5d23e4f6 100644
--- a/raster/r.in.xyz/main.c
+++ b/raster/r.in.xyz/main.c
@@ -857,31 +857,31 @@ int main(int argc, char *argv[])
 
             switch (method) {
             case METHOD_N: /* n is a straight copy */
-                Rast_raster_cpy(raster_row,
-                                n_array +
-                                    (row * cols * Rast_cell_size(CELL_TYPE)),
-                                cols, CELL_TYPE);
+                Rast_raster_cpy(
+                    raster_row,
+                    n_array + ((size_t)row * cols * Rast_cell_size(CELL_TYPE)),
+                    cols, CELL_TYPE);
                 break;
 
             case METHOD_MIN:
-                Rast_raster_cpy(raster_row,
-                                min_array +
-                                    (row * cols * Rast_cell_size(rtype)),
-                                cols, rtype);
+                Rast_raster_cpy(
+                    raster_row,
+                    min_array + ((size_t)row * cols * Rast_cell_size(rtype)),
+                    cols, rtype);
                 break;
 
             case METHOD_MAX:
-                Rast_raster_cpy(raster_row,
-                                max_array +
-                                    (row * cols * Rast_cell_size(rtype)),
-                                cols, rtype);
+                Rast_raster_cpy(
+                    raster_row,
+                    max_array + ((size_t)row * cols * Rast_cell_size(rtype)),
+                    cols, rtype);
                 break;
 
             case METHOD_SUM:
-                Rast_raster_cpy(raster_row,
-                                sum_array +
-                                    (row * cols * Rast_cell_size(rtype)),
-                                cols, rtype);
+                Rast_raster_cpy(
+                    raster_row,
+                    sum_array + ((size_t)row * cols * Rast_cell_size(rtype)),
+                    cols, rtype);
                 break;
 
             case METHOD_RANGE: /* (max-min) */
diff --git a/raster/r.regression.multi/main.c b/raster/r.regression.multi/main.c
index d41afd00f41..fc1ce072c9e 100644
--- a/raster/r.regression.multi/main.c
+++ b/raster/r.regression.multi/main.c
@@ -246,7 +246,7 @@ int main(int argc, char *argv[])
 
     m = &(m_all[0]);
     m->n = n_predictors + 1;
-    m->v = (double *)G_malloc(m->n * m->n * sizeof(double));
+    m->v = (double *)G_malloc((size_t)m->n * m->n * sizeof(double));
 
     a[0] = (double *)G_malloc(m->n * sizeof(double));
     B[0] = (double *)G_malloc(m->n * sizeof(double));
@@ -261,7 +261,7 @@ int main(int argc, char *argv[])
     for (k = 1; k <= n_predictors; k++) {
         m = &(m_all[k]);
         m->n = n_predictors;
-        m->v = (double *)G_malloc(m->n * m->n * sizeof(double));
+        m->v = (double *)G_malloc((size_t)m->n * m->n * sizeof(double));
         a[k] = (double *)G_malloc(m->n * sizeof(double));
         B[k] = (double *)G_malloc(m->n * sizeof(double));
 
diff --git a/raster/r.resamp.filter/main.c b/raster/r.resamp.filter/main.c
index 24043397364..f0ce216c969 100644
--- a/raster/r.resamp.filter/main.c
+++ b/raster/r.resamp.filter/main.c
@@ -168,7 +168,7 @@ static void make_h_weights(void)
 {
     int col;
 
-    h_weights = G_malloc(dst_w.cols * col_scale * sizeof(double));
+    h_weights = G_malloc((size_t)dst_w.cols * col_scale * sizeof(double));
     mapcol0 = G_malloc(dst_w.cols * sizeof(int));
     mapcol1 = G_malloc(dst_w.cols * sizeof(int));
 
@@ -211,7 +211,7 @@ static void make_v_weights(void)
 {
     int row;
 
-    v_weights = G_malloc(dst_w.rows * row_scale * sizeof(double));
+    v_weights = G_malloc((size_t)dst_w.rows * row_scale * sizeof(double));
     maprow0 = G_malloc(dst_w.rows * sizeof(int));
     maprow1 = G_malloc(dst_w.rows * sizeof(int));
 
diff --git a/raster/r.ros/main.c b/raster/r.ros/main.c
index 1d8626c8e68..8c13c7b33c1 100644
--- a/raster/r.ros/main.c
+++ b/raster/r.ros/main.c
@@ -712,8 +712,8 @@ int main(int argc, char *argv[])
             A = 133 / pow(sigma[fuel[col]], 0.7913);
             gammamax = pow(sigma[fuel[col]], 1.5) /
                        (495 + 0.0594 * pow(sigma[fuel[col]], 1.5));
-            gamma =
-                gammamax * pow(beta / betaop, A) * exp(A * (1 - beta / betaop));
+            gamma = gammamax * pow(beta / betaop, A) *
+                    exp((double)A * (1 - beta / betaop));
             xi = exp((0.792 + 0.681 * pow(sigma[fuel[col]], 0.5)) *
                      (beta + 0.1)) /
                  (192 + 0.2595 * sigma[fuel[col]]);
diff --git a/raster/r.ros/spot_dist.c b/raster/r.ros/spot_dist.c
index c8fbedcd02e..1c7ee64877d 100644
--- a/raster/r.ros/spot_dist.c
+++ b/raster/r.ros/spot_dist.c
@@ -99,7 +99,7 @@ int spot_dist(int fuel, float maxros, int speed, float angle, int row0,
 
     /* get I from Byram's equation, I = R*w*h, cited in Rothermel (1991) */
     R = maxros / 60.0;
-    I = R * w[fuel] * 8000;
+    I = (double)R * w[fuel] * 8000;
 
     /* get h0 (originally z0) and z0 (e0 + h0) from Chase (1984) */
     U = 2 * speed / 88.0;
diff --git a/raster/r.sunhours/solpos00.c b/raster/r.sunhours/solpos00.c
index 3f3eff79d41..518da40b367 100644
--- a/raster/r.sunhours/solpos00.c
+++ b/raster/r.sunhours/solpos00.c
@@ -701,7 +701,7 @@ static void sbcf(struct posdata *pdat, struct trigdata *tdat)
     localtrig(pdat, tdat);
     p = 0.6366198 * pdat->sbwid / pdat->sbrad * pow(tdat->cd, 3);
     t1 = tdat->sl * tdat->sd * pdat->ssha * DEG2RAD;
-    t2 = tdat->cl * tdat->cd * sin(pdat->ssha * DEG2RAD);
+    t2 = (double)tdat->cl * tdat->cd * sin(pdat->ssha * DEG2RAD);
     pdat->sbcf = pdat->sbsky + 1.0 / (1.0 - p * (t1 + t2));
 }
 
diff --git a/raster/r.surf.fractal/process.c b/raster/r.surf.fractal/process.c
index 9bce8a11d62..563ebe13970 100644
--- a/raster/r.surf.fractal/process.c
+++ b/raster/r.surf.fractal/process.c
@@ -48,12 +48,12 @@ int process(void)
 
     /*------------------------------------------------------------------*/
 
-    if (nn * nn * sizeof(double) < 1)
+    if ((size_t)nn * nn * sizeof(double) < 1)
         G_fatal_error(_("Unable to allocate data buffer. "
                         "Check current region with g.region."));
 
-    data[0] = (double *)G_malloc(nn * nn * sizeof(double));
-    data[1] = (double *)G_malloc(nn * nn * sizeof(double));
+    data[0] = (double *)G_malloc((size_t)nn * nn * sizeof(double));
+    data[1] = (double *)G_malloc((size_t)nn * nn * sizeof(double));
 
     /*------------------------------------------------------------------*/
     /*                   Apply spectral synthesis algorithm.            */
diff --git a/raster/r.surf.fractal/spec_syn.c b/raster/r.surf.fractal/spec_syn.c
index 23acb75024f..0f9beaf21b8 100644
--- a/raster/r.surf.fractal/spec_syn.c
+++ b/raster/r.surf.fractal/spec_syn.c
@@ -42,8 +42,8 @@ int specsyn(double *data[2], /* Array holding complex data to transform. */
     double phase, rad, /* polar coordinates of Fourier coeff.  */
         *temp[2];
 
-    temp[0] = (double *)G_malloc(nn * nn * sizeof(double));
-    temp[1] = (double *)G_malloc(nn * nn * sizeof(double));
+    temp[0] = (double *)G_malloc((size_t)nn * nn * sizeof(double));
+    temp[1] = (double *)G_malloc((size_t)nn * nn * sizeof(double));
 
     /* ---------------------------------------------------------------- */
     /* ---                   Create fractal surface                 --- */
diff --git a/raster/r.texture/h_measure.c b/raster/r.texture/h_measure.c
index d07078fd35c..4ff533ff8ce 100644
--- a/raster/r.texture/h_measure.c
+++ b/raster/r.texture/h_measure.c
@@ -405,7 +405,7 @@ float f12_icorr(struct matvec *mv)
     for (i = 0; i < Ng; i++) {
         for (j = 0; j < Ng; j++) {
             if (px[i] * py[j] > 0)
-                hxy1 -= P[i][j] * log2(px[i] * py[j]);
+                hxy1 -= P[i][j] * log2((double)px[i] * py[j]);
             if (P[i][j] > 0)
                 hxy -= P[i][j] * log2(P[i][j]);
         }
@@ -437,7 +437,7 @@ float f13_icorr(struct matvec *mv)
     for (i = 0; i < Ng; i++) {
         for (j = 0; j < Ng; j++) {
             if (px[i] * py[j] > 0)
-                hxy2 -= px[i] * py[j] * log2(px[i] * py[j]);
+                hxy2 -= (double)px[i] * py[j] * log2((double)px[i] * py[j]);
             if (P[i][j] > 0)
                 hxy -= P[i][j] * log2(P[i][j]);
         }
diff --git a/raster/r.viewshed/eventlist.cpp b/raster/r.viewshed/eventlist.cpp
index 03a75a78cf1..d637bbc28ec 100644
--- a/raster/r.viewshed/eventlist.cpp
+++ b/raster/r.viewshed/eventlist.cpp
@@ -62,7 +62,8 @@ double calculate_center_gradient(AEvent *e, Viewpoint *vp)
     sqdist = (e->row - vp->row) * (e->row - vp->row) +
              (e->col - vp->col) * (e->col - vp->col);
 
-    gradient = (e->elev[1] - vp->elev) * (e->elev[1] - vp->elev) / sqdist;
+    gradient =
+        (double)(e->elev[1] - vp->elev) * (e->elev[1] - vp->elev) / sqdist;
     /*maintain sign */
     if (e->elev[1] < vp->elev)
         gradient = -gradient;
diff --git a/raster/r.viewshed/viewshed.cpp b/raster/r.viewshed/viewshed.cpp
index b742e70cdc0..fbe7d26a145 100644
--- a/raster/r.viewshed/viewshed.cpp
+++ b/raster/r.viewshed/viewshed.cpp
@@ -121,7 +121,7 @@ AEvent *allocate_eventlist(GridHeader *hd)
 
     AEvent *eventList;
 
-    long long totalsize = hd->ncols * hd->nrows * 3;
+    long long totalsize = (long long)hd->ncols * hd->nrows * 3;
 
     totalsize *= sizeof(AEvent);
     G_debug(1, "total size of eventlist is %lld B (%d MB);  ", totalsize,
@@ -195,7 +195,7 @@ MemoryVisibilityGrid *viewshed_in_memory(char *inputfname, GridHeader *hd,
     assert(visgrid);
     G_debug(1, "visibility grid size:  %d x %d x %d B (%d MB)", hd->nrows,
             hd->ncols, (int)sizeof(float),
-            (int)(((long long)(hd->nrows * hd->ncols * sizeof(float))) >> 20));
+            (int)(((long long)hd->nrows * hd->ncols * sizeof(float)) >> 20));
 
     /* ------------------------------ */
     /* construct the event list corresponding to the given input file
diff --git a/raster/r.watershed/ram/flag_create.c b/raster/r.watershed/ram/flag_create.c
index 20acb4fc2fe..85f2f19b4f5 100644
--- a/raster/r.watershed/ram/flag_create.c
+++ b/raster/r.watershed/ram/flag_create.c
@@ -14,7 +14,7 @@ FLAG *flag_create(int nrows, int ncols)
     new_flag->array =
         (unsigned char **)G_malloc(nrows * sizeof(unsigned char *));
 
-    temp = (unsigned char *)G_malloc(nrows * new_flag->leng *
+    temp = (unsigned char *)G_malloc((size_t)nrows * new_flag->leng *
                                      sizeof(unsigned char));
 
     for (i = 0; i < nrows; i++) {
diff --git a/raster/r.watershed/ram/ramseg.c b/raster/r.watershed/ram/ramseg.c
index 7e9393fc5f4..157cebc90db 100644
--- a/raster/r.watershed/ram/ramseg.c
+++ b/raster/r.watershed/ram/ramseg.c
@@ -23,7 +23,7 @@ size_t seg_index_rc(int ramseg, size_t seg_index, int *r, int *c)
     seg_no = seg_index >> DOUBLEBITS;
     seg_remainder = seg_index - (seg_no << DOUBLEBITS);
     *r = ((seg_no / ramseg) << RAMSEGBITS) + (seg_remainder >> RAMSEGBITS);
-    *c = ((seg_no - ((*r) >> RAMSEGBITS) * ramseg) << RAMSEGBITS) +
+    *c = ((seg_no - (size_t)((*r) >> RAMSEGBITS) * ramseg) << RAMSEGBITS) +
          seg_remainder - (((*r) & SEGLENLESS) << RAMSEGBITS);
     return seg_no;
 }