diff --git a/src/option.c b/src/option.c
index cd50e8d..4856a59 100644
--- a/src/option.c
+++ b/src/option.c
@@ -7454,11 +7454,17 @@
 #endif /* FEAT_INS_EXPAND */
 
 #ifdef FEAT_SIGNS
-    /* 'signcolumn' */
+    // 'signcolumn'
     else if (varp == &curwin->w_p_scl)
     {
 	if (check_opt_strings(*varp, p_scl_values, FALSE) != OK)
 	    errmsg = e_invarg;
+	// When changing the 'signcolumn' to or from 'number', recompute the
+	// width of the number column if 'number' or 'relativenumber' is set.
+	if (((*oldval == 'n' && *(oldval + 1) == 'u')
+		|| (*curwin->w_p_scl == 'n' && *(curwin->w_p_scl + 1) =='u'))
+		&& (curwin->w_p_nu || curwin->w_p_rnu))
+	    curwin->w_nrwidth_line_count = 0;
     }
 #endif