diff --git a/configure.in b/configure.in
index 8902de42..6f75ef9e 100644
--- a/configure.in
+++ b/configure.in
@@ -345,8 +345,8 @@ CS_NUM_WITH([luks1-keybits],[key length in bits for LUKS1], [256])
 CS_STR_WITH([loopaes-cipher], [cipher for loop-AES mode], [aes])
 CS_NUM_WITH([loopaes-keybits],[key length in bits for loop-AES mode], [256])
 
-CS_NUM_WITH([keyfile-size-maxkb],[maximum keyfile size (in kilobytes)], [8192])
-CS_NUM_WITH([passphrase-size-max],[maximum keyfile size (in kilobytes)], [512])
+CS_NUM_WITH([keyfile-size-maxkb],[maximum keyfile size (in KiB)], [8192])
+CS_NUM_WITH([passphrase-size-max],[maximum keyfile size (in characters)], [512])
 
 CS_STR_WITH([verity-hash],       [hash function for verity mode], [sha256])
 CS_NUM_WITH([verity-data-block], [data block size for verity mode], [4096])