IPSec Packet Size Calculator

IP Packet Size (not including Ethernet headers)
bytes             

Mode
Transport
Tunnel

GRE (usually not needed for transport mode)

NAT-T (If NAT Transerval is used)

ESP
none ESP-DES ESP-3DES ESP-null none esp-md5-hmac esp-sha-hmac

AH
none ah-md5-hmac ah-sha-hmac

bytes after IPsec transform