diff --git a/scapy/sendrecv.py b/scapy/sendrecv.py
index c4024eefc8af3804c4e891f432c672a8752482e6..837171b6f93a37394362b7dd7cc8b6f02d6ea3f4 100644
--- a/scapy/sendrecv.py
+++ b/scapy/sendrecv.py
@@ -273,9 +273,9 @@ def sendpfast(x, pps=None, mbps=None, realtime=None, loop=0, file_cache=False, i
     if pps is not None:
         argv.append("--pps=%i" % pps)
     elif mbps is not None:
-        argv.append("--mbps=%i" % mbps)
+        argv.append("--mbps=%f" % mbps)
     elif realtime is not None:
-        argv.append("--multiplier=%i" % realtime)
+        argv.append("--multiplier=%f" % realtime)
     else:
         argv.append("--topspeed")