.NRT File

File extension nrt is mainly related to ringtones used on some older types of mobile phones developed by Nokia (now owned by Microsoft).

A .nrt file contains ringtone stored in audio file format similar to MIDI.

Files with nrt suffix can be found as ringtones for some older Nokia mobile phone devices.

How to open:

Nokia Suite can create and handle .nrt ringtones. Same program can upload them to your Nokia device.

How to convert:

Possibly can be converted to other audio formats, provided you find a converter that will recognize this audio format.