diff --git a/awesome.c b/awesome.c
index 49785afe2..af5c24466 100644
--- a/awesome.c
+++ b/awesome.c
@@ -409,8 +409,8 @@ main(int argc, char **argv)
 
     /* init default font and colors */
     globalconf.font = draw_font_new(globalconf.connection, globalconf.default_screen, "sans 8");
-    xcolor_init(&globalconf.colors.fg, globalconf.connection, globalconf.default_screen, "black", sizeof("black"));
-    xcolor_init(&globalconf.colors.bg, globalconf.connection, globalconf.default_screen, "white", sizeof("white"));
+    xcolor_init(&globalconf.colors.fg, globalconf.connection, globalconf.default_screen, "black", sizeof("black")-1);
+    xcolor_init(&globalconf.colors.bg, globalconf.connection, globalconf.default_screen, "white", sizeof("white")-1);
 
     /* init cursors */
     globalconf.cursor[CurNormal] = xutil_cursor_new(globalconf.connection, CURSOR_LEFT_PTR);
diff --git a/common/socket.c b/common/socket.c
index 4c4b7e0aa..5070defb3 100644
--- a/common/socket.c
+++ b/common/socket.c
@@ -58,7 +58,7 @@ socket_getaddr(const char *display)
 
     /* a_strlen(display) because we strcat on display and
      * + 2 for / and \0 */
-    path_len = a_strlen(homedir) + sizeof(CONTROL_UNIX_SOCKET_PATH)
+    path_len = a_strlen(homedir) + sizeof(CONTROL_UNIX_SOCKET_PATH)-1
                + (display_len ? (a_strlen(real_display)) : 1) + 2;
 
     if(path_len >= ssizeof(addr->sun_path))
diff --git a/common/xutil.c b/common/xutil.c
index 77b4e8340..96f36345c 100644
--- a/common/xutil.c
+++ b/common/xutil.c
@@ -497,7 +497,7 @@ xutil_cursor_new(xcb_connection_t *conn, unsigned int cursor_font)
 
     /* Get the font for the cursor*/
     font = xcb_generate_id(conn);
-    xcb_open_font(conn, font, sizeof("cursor"), "cursor");
+    xcb_open_font(conn, font, sizeof("cursor")-1, "cursor");
 
     cursor = xcb_generate_id(conn);
     xcb_create_glyph_cursor(conn, cursor, font, font,
diff --git a/lua.c b/lua.c
index 2907db16a..0b21e940e 100644
--- a/lua.c
+++ b/lua.c
@@ -537,14 +537,14 @@ luaA_parserc(const char *confpatharg)
 
     if(a_strlen(confdir))
     {
-        len = a_strlen(confdir) + sizeof(AWESOME_CONFIG_FILE) + 1;
+        len = a_strlen(confdir) + sizeof(AWESOME_CONFIG_FILE);
         confpath = p_new(char, len);
         a_strcpy(confpath, len, confdir);
     }
     else
     {
         confdir = getenv("HOME");
-        len = a_strlen(confdir) + sizeof(AWESOME_CONFIG_FILE) + sizeof(XDG_CONFIG_HOME_DEFAULT) + 1;
+        len = a_strlen(confdir) + sizeof(AWESOME_CONFIG_FILE)-1 + sizeof(XDG_CONFIG_HOME_DEFAULT);
         confpath = p_new(char, len);
         a_strcpy(confpath, len, confdir);
         a_strcat(confpath, len, XDG_CONFIG_HOME_DEFAULT);
@@ -561,7 +561,7 @@ luaA_parserc(const char *confpatharg)
     if(!(len = a_strlen(xdg_config_dirs)))
     {
         xdg_config_dirs = SYSCONFDIR;
-        len = sizeof(SYSCONFDIR);
+        len = sizeof(SYSCONFDIR)-1;
     }
 
     xdg_files = a_strsplit(xdg_config_dirs, len, ':');
@@ -569,7 +569,7 @@ luaA_parserc(const char *confpatharg)
     for(buf = xdg_files; *buf; buf++)
     {
         p_delete(&confpath);
-        len = a_strlen(*buf) + sizeof("AWESOME_CONFIG_FILE") + 1;
+        len = a_strlen(*buf) + sizeof("AWESOME_CONFIG_FILE");
         confpath = p_new(char, len);
         a_strcpy(confpath, len, *buf);
         a_strcat(confpath, len, AWESOME_CONFIG_FILE);
@@ -587,7 +587,7 @@ luaA_parserc(const char *confpatharg)
     /* Assure there's at least one tag */
     for(screen = 0; screen < globalconf.screens_info->nscreen; screen++)
         if(!globalconf.screens[screen].tags.len)
-            tag_append_to_screen(tag_new("default", sizeof("default"), layout_tile, 0.5, 1, 0), screen);
+            tag_append_to_screen(tag_new("default", sizeof("default")-1, layout_tile, 0.5, 1, 0), screen);
 
     p_delete(&confpath);
 }
diff --git a/mouse.c b/mouse.c
index 9da99bacf..3e4a2d8e1 100644
--- a/mouse.c
+++ b/mouse.c
@@ -276,7 +276,7 @@ mouse_infobox_new(int phys_screen, int border, area_t geometry,
                              globalconf.default_screen,
                              globalconf.font,
                              MOUSE_INFOBOX_STRING_DEFAULT,
-                             sizeof(MOUSE_INFOBOX_STRING_DEFAULT),
+                             sizeof(MOUSE_INFOBOX_STRING_DEFAULT)-1,
                              &pdata);
     geom.x = geometry.x + ((2 * border + geometry.width) - geom.width) / 2;
     geom.y = geometry.y + ((2 * border + geometry.height) - geom.height) / 2;