diff --git a/Documentation/deprecated.txt b/Documentation/deprecated.txt
index 9a2198014..5113594ac 100644
--- a/Documentation/deprecated.txt
+++ b/Documentation/deprecated.txt
@@ -2,6 +2,11 @@ The following is a list of commands or features that are deprecated.  All
 deprecated utils are in maintenance mode and we keep them in source tree for
 backward compatibility only.
 
+What:   fdisk -s <device>
+Why:    this does not belong to fdisk, use "blockdev --getsz"
+
+--------------------------
+
 What:   'udev' and 'list' blkid(8) output formats
 Why:    udevd links libblkid directly; the 'list' is unnecessary, use lsblk(8)
 
diff --git a/fdisks/fdisk.8 b/fdisks/fdisk.8
index 9e81eb23c..439f0f62f 100644
--- a/fdisks/fdisk.8
+++ b/fdisks/fdisk.8
@@ -225,7 +225,9 @@ If no devices are given, those mentioned in
 (if that exists) are used.
 .TP
 .BI "\-s " partition...
-Print the size (in blocks) of each given partition.
+Print the size (in blocks) of each given partition. This option is DEPRECATED
+in favour of
+.B blockdev (1).
 .TP
 .BI "\-u"[=unit]
 When listing partition tables, show sizes in 'sectors' or in 'cylinders'.  The
diff --git a/fdisks/fdisk.c b/fdisks/fdisk.c
index 36d426611..905aaa193 100644
--- a/fdisks/fdisk.c
+++ b/fdisks/fdisk.c
@@ -53,7 +53,7 @@ static void __attribute__ ((__noreturn__)) usage(FILE *out)
 	fprintf(out,
 	      _(" %1$s [options] <disk>    change partition table\n"
 	        " %1$s [options] -l <disk> list partition table(s)\n"
-	        " %1$s -s <partition>      give partition size(s) in blocks\n"),
+	        " %1$s -s <partition>      give partition size(s) in blocks (deprecated)\n"),
 	       program_invocation_short_name);
 
 	fputs(USAGE_OPTIONS, out);
@@ -451,6 +451,7 @@ int main(int argc, char **argv)
 		break;
 
 	case ACT_SHOWSIZE:
+		/* deprecated */
 		if (argc - optind <= 0)
 			usage(stderr);