diff --git a/src/avrdude.1 b/src/avrdude.1
index d963fd13..c23d4c1d 100644
--- a/src/avrdude.1
+++ b/src/avrdude.1
@@ -377,7 +377,7 @@ to trigger programming mode for certain boards like Arduino Leonardo,
 Arduino Micro/Pro Micro and the Arduino Nano Every. Longer waits, and
 therefore multiple -r options, are sometimes needed for slower, less
 powerful hosts.
-.It Fl B \-bitclock
+.It Fl B \-bitclock Ar bitclock
 Specify the bit clock period for the JTAG, PDI, TPI, UPDI, or ISP
 interface. The value is a floating-point number in microseconds.
 Alternatively, the value might be suffixed with "Hz", "kHz" or