diff --git a/bin/df/df.1 b/bin/df/df.1
index bf461d62e2b..835ff232710 100644
--- a/bin/df/df.1
+++ b/bin/df/df.1
@@ -39,7 +39,7 @@
 .Nd display free disk space
 .Sh SYNOPSIS
 .Nm df
-.Op Fl in
+.Op Fl ink
 .Op Fl t Ar type
 .Op Ar file | Ar filesystem ...
 .Sh DESCRIPTION
@@ -60,6 +60,11 @@ The following options are available:
 .Bl -tag -width Ds
 .It Fl i
 Include statistics on the number of free inodes.
+.It Fl k
+Use 1024-byte (1-Kbyte) blocks rather than the default.  Note that
+this overrides the
+.Ev BLOCKSIZE
+specification from the environment.
 .It Fl n
 Print out the previously obtained statistics from the filesystems.
 This option should be used if it is possible that one or more
diff --git a/bin/df/df.c b/bin/df/df.c
index eb6ee81a436..02e6ca92535 100644
--- a/bin/df/df.c
+++ b/bin/df/df.c
@@ -121,11 +121,14 @@ main(argc, argv)
 	int ch, err, i, maxwidth, width;
 	char *mntpt;
 
-	while ((ch = getopt(argc, argv, "int:")) != EOF)
+	while ((ch = getopt(argc, argv, "iknt:")) != EOF)
 		switch (ch) {
 		case 'i':
 			iflag = 1;
 			break;
+		case 'k':
+			putenv("BLOCKSIZE=1024");
+			break;
 		case 'n':
 			nflag = 1;
 			break;
@@ -415,6 +418,7 @@ bread(off, buf, cnt)
 void
 usage()
 {
-	(void)fprintf(stderr, "usage: df [-in] [file | file_system ...]\n");
+	fprintf(stderr, 
+		"usage: df [-ikn] [-t fstype] [file | file_system ...]\n");
 	exit(1);
 }