MTU & MSS Calculator

Determine the optimal MTU and TCP MSS values for your network. Account for encapsulation overhead from tunnels and various transport protocols to prevent fragmentation.

Base Configuration

Physical Interface MTU

Standard Ethernet is 1500. Jumbo frames typically 9000+.

Protocol Overheads

IPv4 Header Standard IP routing overhead

20B

TCP Header Base transport layer overhead

20B

IPsec ESP VPN Tunnel mode encryption (estimated)

+36B

Encryption Algorithm Include NAT-T (UDP 4500) overhead (+8B)

GRE Tunnel Generic Routing Encapsulation

+24B

VxLAN Virtual Extensible LAN (UDP 4789)

+50B

802.1Q Tag Standard VLAN tagging

+4B

PPPoE DSL/Fiber broadband encapsulation

+8B