diff --git a/README.md b/README.md
index fca20e5..23a1cc2 100644
--- a/README.md
+++ b/README.md
@@ -1,7 +1,7 @@
 # ipfs-key
 A tool for easily generating ipfs keypairs. When run, it will write the bytes of
 the serialized private key to stdout. By default, a 2048 bit RSA key will be
-generated. The keysize can be changed by specifying the `-size` option, and the
+generated. The keysize can be changed by specifying the `-bitsize` option, and the
 key type can be changed by specifying the `-type` option (currently only RSA is
 implemented).
 
@@ -12,5 +12,5 @@ $ go get github.com/whyrusleeping/ipfs-key
 
 ## Usage
 ```
-$ ipfs-key -size=4096 > my.key
+$ ipfs-key -bitsize=4096 > my.key
 ```