Networking

MTU Calculator

MTU Size (bytes)

Maximum Payload by Protocol

Protocol Stack	Overhead	Max Payload
Raw Ethernet	0 bytes	1500 bytes
IPv4 only	20 bytes	1480 bytes
IPv6 only	40 bytes	1460 bytes
IPv4 + TCP	40 bytes	1460 bytes
IPv4 + UDP	28 bytes	1472 bytes
IPv6 + TCP	60 bytes	1440 bytes
IPv6 + UDP	48 bytes	1452 bytes
IPv4 + ICMP	28 bytes	1472 bytes
IPv4 + TCP + TLS (est.)	80 bytes	1420 bytes

TCP Maximum Segment Size (MSS)

IPv4 MSS

IPv6 MSS

MSS = MTU - IP Header (20/40 bytes) - TCP Header (20 bytes)

Recommended MTU with Tunneling

PPPoE (8 bytes)

IPsec ESP (50-57 bytes)

GRE (24 bytes)

WireGuard (60 bytes)

OpenVPN UDP (28 bytes)

VXLAN (50 bytes)

About MTU

MTU (Maximum Transmission Unit) is the largest packet size that can be sent over a network. Setting MTU correctly prevents fragmentation and improves performance.

Common MTU values:

1500: Standard Ethernet
1492: PPPoE (DSL)
1400: Safe for most VPNs
9000: Jumbo frames (datacenter)
576: Minimum IPv4 MTU
1280: Minimum IPv6 MTU