MTU Overhead Calculator
Underlay
The IP MTU of the link the outermost layer runs over.
1500 for standard Ethernet, 9000 or 9216 for jumbo frames.
Tags grow the Ethernet frame but don't reduce the IP MTU.
Encapsulation stack
Add layers outermost first. Each layer takes its overhead out of the MTU left by the one before it.
Common stacks:
No layers yet: the inner MTU equals the underlay MTU.
The underlay MTU you'd need to carry this much inside the stack unfragmented.
Results
| Layer | Overhead | MTU left |
|---|
ESP overhead includes the block padding needed at this size, so it can vary by a few bytes as the underlay MTU changes.