diff --git a/src/move.c b/src/move.c
index 7fe82b9..b1a6119 100644
--- a/src/move.c
+++ b/src/move.c
@@ -475,13 +475,14 @@ void do_down(bool scroll_only)
 #ifndef NANO_TINY
     if (ISSET(SOFTWRAP)) {
 	/* Compute the number of lines to scroll. */
-	amount = strlenpt(openfile->current->data) / COLS - xplustabs() / COLS +
-			strlenpt(openfile->current->next->data) / COLS +
+	amount = strlenpt(openfile->current->data) / (COLS - margin) -
+			xplustabs() / (COLS -margin) +
+			strlenpt(openfile->current->next->data) / (COLS - margin) +
 			openfile->current_y - editwinrows + 2;
 	topline = openfile->edittop;
 	/* Reduce the amount when there are overlong lines at the top. */
 	for (enough = 1; enough < amount; enough++) {
-	    amount -= strlenpt(topline->data) / COLS;
+	    amount -= strlenpt(topline->data) / (COLS - margin);
 	    if (amount > 0)
 		topline = topline->next;
 	    if (amount < enough) {
diff --git a/src/winio.c b/src/winio.c
index ae73f92..639bc9b 100644
--- a/src/winio.c
+++ b/src/winio.c
@@ -2253,7 +2253,7 @@ void edit_draw(filestruct *fileptr, const char *converted, int
     size_t startpos = actual_x(fileptr->data, start);
 	/* The position in fileptr->data of the leftmost character
 	 * that displays at least partially on the window. */
-    size_t endpos = actual_x(fileptr->data, start + COLS - 1) + 1;
+    size_t endpos = actual_x(fileptr->data, start + COLS - margin - 1) + 1;
 	/* The position in fileptr->data of the first character that is
 	 * completely off the window to the right.
 	 *
@@ -2262,7 +2262,7 @@ void edit_draw(filestruct *fileptr, const char *converted, int
 #endif
 
     assert(openfile != NULL && fileptr != NULL && converted != NULL);
-    assert(strlenpt(converted) <= COLS);
+    assert(strlenpt(converted) <= COLS - margin);
 
 #ifdef ENABLE_LINENUMBERS
     if (ISSET(LINE_NUMBERS)) {
@@ -2529,7 +2529,7 @@ void edit_draw(filestruct *fileptr, const char *converted, int
 					strnlenpt(fileptr->data,
 					endmatch.rm_eo) - start - x_start);
 
-			    assert(0 <= x_start && x_start < COLS);
+			    assert(0 <= x_start && x_start < COLS - margin);
 
 			    mvwaddnstr(edit, line, x_start + margin,
 					converted + index, paintlen);
@@ -2558,7 +2558,7 @@ void edit_draw(filestruct *fileptr, const char *converted, int
 			if (end_line == NULL)
 			    break;
 
-			assert(0 <= x_start && x_start < COLS);
+			assert(0 <= x_start && x_start < COLS - margin);
 
 			/* Paint the rest of the line. */
 			mvwaddnstr(edit, line, x_start + margin, converted + index, -1);
@@ -2693,11 +2693,11 @@ int update_line(filestruct *fileptr, size_t index)
     /* Expand the line, replacing tabs with spaces, and control
      * characters with their displayed forms. */
 #ifdef NANO_TINY
-    converted = display_string(fileptr->data, page_start, COLS, TRUE);
+    converted = display_string(fileptr->data, page_start, COLS - margin, TRUE);
 #else
-    converted = display_string(fileptr->data, page_start, COLS, !ISSET(SOFTWRAP));
+    converted = display_string(fileptr->data, page_start, COLS - margin, !ISSET(SOFTWRAP));
 #ifdef DEBUG
-    if (ISSET(SOFTWRAP) && strlen(converted) >= COLS - 2)
+    if (ISSET(SOFTWRAP) && strlen(converted) >= COLS - margin - 2)
 	fprintf(stderr, "update_line(): converted(1) line = %s\n", converted);
 #endif
 #endif /* !NANO_TINY */
@@ -2725,9 +2725,9 @@ int update_line(filestruct *fileptr, size_t index)
 
 	    /* Expand the line, replacing tabs with spaces, and control
 	     * characters with their displayed forms. */
-	    converted = display_string(fileptr->data, index, COLS, !ISSET(SOFTWRAP));
+	    converted = display_string(fileptr->data, index, COLS - margin, !ISSET(SOFTWRAP));
 #ifdef DEBUG
-	    if (ISSET(SOFTWRAP) && strlen(converted) >= COLS - 2)
+	    if (ISSET(SOFTWRAP) && strlen(converted) >= COLS - margin - 2)
 		fprintf(stderr, "update_line(): converted(2) line = %s\n", converted);
 #endif
 
@@ -2993,7 +2993,7 @@ void edit_update(update_type manner)
 	    goal = editwinrows - 1;
 #ifndef NANO_TINY
 	    if (ISSET(SOFTWRAP))
-		goal -= strlenpt(openfile->current->data) / COLS ;
+		goal -= strlenpt(openfile->current->data) / (COLS - margin);
 #endif
 	}
     } else {
@@ -3133,7 +3133,7 @@ void spotlight(bool active, const char *word)
     size_t word_len = strlenpt(word), room;
 
     /* Compute the number of columns that are available for the word. */
-    room = COLS + get_page_start(xplustabs()) - xplustabs();
+    room = COLS - margin + get_page_start(xplustabs()) - xplustabs();
 
     assert(room > 0);
 
@@ -3273,7 +3273,7 @@ void do_credits(void)
 	    } else
 		what = credits[crpos];
 
-	    start_x = COLS / 2 - strlenpt(what) / 2 - 1;
+	    start_x = (COLS - margin) / 2 - strlenpt(what) / 2 - 1;
 	    mvwaddstr(edit, editwinrows - 1 - (editwinrows % 2),
 		start_x, what);
 	}