MTU Finder — Path MTU Test

Yasin Güven

About this app

Find the largest packet that actually reaches a host without being fragmented — the path MTU — straight from your phone.

If your VPN keeps stalling, some websites load while others hang forever, or SSH freezes on large output, a wrong MTU is a common cause. This app measures it instead of making you guess.

HOW IT WORKS
Type a host — 8.8.8.8, your router, your VPN endpoint, any name or address — and start the test. The app sends ping packets with the "don't fragment" flag set and narrows in with a binary search, so it finds the exact boundary in about a dozen probes rather than hundreds.

WHAT YOU SEE
• The path MTU in bytes, ready to put into your router or VPN config
• The size being probed at each step, so you can watch the search converge
• The MTU your device reports for each of its own network interfaces — useful for comparing Wi-Fi against mobile data
• Your last five results, so you don't have to write them down

NOTES
• Some hosts drop ICMP entirely. If a test fails, try another target such as 8.8.8.8 or 1.1.1.1.
• The result describes the path from this phone to that host on the network you are on right now. Change networks and it can change.

PRIVACY
• No ads, no analytics, no accounts
• Results stay on your device
• The only traffic is the ping probes you ask for

LANGUAGES
Arabic, Chinese (Simplified), Chinese (Traditional), English, French, German, Italian, Japanese, Korean, Portuguese, Russian, Spanish and Turkish.

Requires Android 8.0 or later.

What’s new

- Fixed an accuracy issue: a response from another device on the network was sometimes mistaken for the app's own test result.
- Easier to use with a remote control or keyboard: links, the address field, and the Start button now show a clear focus outline, and moving down from the address field now reaches the Start button.