diff --git a/bin/df/df.c b/bin/df/df.c
index db5b8b18beae00..0f9f6e1f21b8e6 100644
--- a/bin/df/df.c
+++ b/bin/df/df.c
@@ -128,11 +128,12 @@ main(int argc, char *argv[])
 			/*
 			 * POSIX specifically discusses the behavior of
 			 * both -k and -P. It states that the blocksize should
-			 * be set to 1024. Thus, if this occurs, simply break
-			 * rather than clobbering the old blocksize.
+			 * be set to 1024.
 			 */
-			if (kflag)
+			if (kflag) {
+                setenv("BLOCKSIZE", "1024", 1);
 				break;
+            }
 			setenv("BLOCKSIZE", "512", 1);
 			hflag = 0;
 			break;
@@ -154,7 +155,7 @@ main(int argc, char *argv[])
 			break;
 		case 'k':
 			kflag++;
-			setenv("BLOCKSIZE", "1024", 1);
+			setenv("BLOCKSIZE", "1k", 1);
 			hflag = 0;
 			break;
 		case 'l':