Networking & IT Tools

MTU Overhead Calculator

Enter your link MTU and choose an encapsulation type to calculate the effective payload MTU after overhead.

1492 bytes
effective payload MTU (1500 link MTU − 8 bytes overhead)

Overhead figures are commonly cited approximations — actual overhead varies by exact protocol options and header fields in use, so measure or check your specific tunnel/VPN configuration for precise numbers.

How to use this tool

  1. 1Enter your link's MTU in bytes.
  2. 2Choose an encapsulation preset or enter a custom overhead.
  3. 3See the effective payload MTU.

Frequently asked questions

Why does PPPoE reduce MTU to 1492?+

PPPoE adds an 8-byte header on top of standard 1500-byte Ethernet, leaving 1492 bytes for the actual payload — a very common real-world MTU value on DSL connections.

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