- Figure out which part of the song you want for your ringtone. You'll need to remember the start and stop time down to the second.
- Right click on the song and select "Get Info."
- Select the Options tab. Remember those numbers from Step 1? Plug them in for the start time and stop time, then click OK.
Listen to the song again. You'll need to make sure it's the length you want, so adjust the start and stop time until it's perfect.
Right click the song again and select “Create AAC Version.” After you do this, you'll notice that there are now two versions of the song in your iTunes library.
Right click on the new file. Select “Show in Finder” if you’re on a Mac, or select “Show in Windows Explorer” on a PC. That'll open up a new window and bring up both versions of the song in the iTunes Media folder. The one you want will be highlighted.
Right click, select "Get Info" and rename with .m4r. We need our file to be in this format so it can be recognized as a ringtone. My song currently reads "06 Shake It Off 1.m4a,' so I change it to say "06 Shake It Off.m4r." Then I hit enter.
Once you do so, it’ll ask permission to say it will be a different file type. Select "Use .m4r."
- Copy the .m4r file to your desktop. Go back to iTunes and delete the shortened version of the song by right clicking and selecting "Delete."
- Drag the file from your desktop to your iTunes library under Music. It will then appear in your Tones section.
- Sync your iPhone to your computer. While still in your iPhone menu on iTunes, go to Tones and select Sync Tones. Then hit "Sync" or "Apply."
ringtone sync tones
Now, the ringtone is ready to go. On your iPhone, go to Settings > Sounds > Ringtone and your new tone will be above the built-in ones.
src : http://www.huffingtonpost.com/2014/10/02/make-free-ringtone-iphone_n_5901540.html