The iPhone comes with a small selection of default ringtones, but you can make your own using any mp3 or DRM-free song in iTunes. Below are step-by-step instructions on how to do this.
How to Make an iPhone Ringtone in iTunes:
1. Open iTunes.
2. Open Preferences in the iTunes menu at the top:

3. Select the General tab:

4. Select Import Settings:

5. Click on the dropdown list after Importing Using:

6. Select AAC Encoder (it may already be the default):

7. Select OK to go back to the Preferences, then select OK again.

8. Select Music in the left iTunes sidebar and find a song you want to make into a ringtone:

9. You’ll need to find a 40 second or less section of the song to turn into a ringtone. Note (or write down) the starting and stopping point of the section of the song. You can see the time of the song in the play window at the top of iTunes:

10. Right click on the song, and select Get Info:

11. Select the Options tab at the top:

12. Enter the start and stop time of the clip in the corresponding boxes and make sure the checkboxes are checked when you are finished:

13. Click OK in the bottom right.
14. Right click the song again and select Create AAC Version:

15. You should see a second version of the song appear in iTunes, only with the shorter play time. Click to play to make sure it sounds how you’ll want the ringtone to sound.

16. We aren’t quite finished yet! Now we have to change the file format so that it will appear as a ringtone in iTunes.
17. Navigate to the folder where the new clip is stored on your computer (it will be in the same folder as the original version of the song). If you’re on a Mac, simply right-click the clip and select Show In Finder.
18. Copy the song (press Control and C for Windows, Command and C for Mac), and paste the song in the same folder (Control and V or Command and V) so that a third version appears.

19. Now, change the file extension of the third version from .m4a to .m4r. If you’re on Windows XP and don’t see the file extension, go to Tools –> Folder Options –> View and uncheck Hide extensions for known file types. For Vista: Organize –> Folder and Search Options and uncheck Hide extension for known file types.

20. Rename the file, if you want (for example, AfromanRingtone.m4r). Note: If there are symbols such as underscores or hyphens in the name you must remove them from the name.
21. Important: In iTunes, delete the first AAC clip you made by right-clicking on the clip and selecting delete (if you don’t do this, iTunes might not accept the new ringtone):

22. Go back to the folder with the new ringtone file (.m4r file). Drag and drop the file into iTunes. Or import it by opening iTunes, select File, and select: Windows XP/Vista: Add File to Library, Mac: Add to Library.

23. Now we need to sync the ringtone to your iPhone. Connect the iPhone to the computer.

24. Click on your iPhone in the left sidebar in iTunes:

25. Click on the Ringtones tab, check the Sync ringtones checkbox, then check All ringtones or Selected ringtones.:
26. Now click the Apply button in the bottom right (it may also say Sync. Click Sync if it does).

And that’s it. You’ve done it! the ringtone is now on the iPhone. Got to Settings on your iPhone, tap Sounds, and you can change to your new ringtone.
Clean Up
You made the ringtone, but you’ve left a little mess behind. Let’s clean up. First, we need to fix the Start/Stop time of the original song. Otherwise, the next time you play the song, it won’t play the whole thing. In iTunes, right click the original song, select Get Info –> Options and reset the Start/Stop time by deleting the numbers and leaving the fields blank. Next, delete the second version of song you created (not the ringtone). Just right click and select Delete.
Troubleshooting
If you’re having problems getting the ringtones to sync from iTunes onto the iPhone, here’s another trick to try (first confirm there are no hyphens or other symbols in name, and the ringtone is not over 40 seconds).
Create a playlist by going to File–>New Playlist. Name it Ringtones and add your ringtones to it by dragging and dropping them on the playlist. Still in iTunes, click on your iPhone under Devices in the left sidebar, select the Music tab, check the Sync music checkbox, then either click All songs and playlists if you have enough memory on your iPhone, or Selected playlists and check the checkbox for the Ringtones playlist you just created. Now sync.

#1 by Tim on February 26th, 2010
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You rock!
#2 by Jackfish on February 26th, 2010
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The most concise, clear and easy to follow instructions that I have seen. Thank you very much!
#3 by Stefany on February 27th, 2010
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Hi,
Sorryyy, but I followed all the steps that you listed out, but when I went to sync my phone to iTunes, it said that the file could not be found….
What do I do?!
#4 by Stefany on February 27th, 2010
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Actually, I take that back. It was able to sync to my iPhone, but it does not show on Settings->Sounds->Ringtones
#5 by Tony on February 28th, 2010
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It works great. If some of you didn’t get it right, you probably did something wrong. Just like I did at first. Pay attention to each step, don’t have it longer than 40secs and clean the mess…
#6 by Chris on February 28th, 2010
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Thanks!!!
#7 by Jack on March 1st, 2010
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You Rock!! Perfect!!
#8 by Lee on March 1st, 2010
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Thank you so much!
Love the graphics and easy to follow directions!!!
#9 by Amani on March 2nd, 2010
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You are brilliant! Thank you so much!!
#10 by yusuf on March 2nd, 2010
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The m4r file land up in the itunes music library , but not under the ringtones folder. How do I move it to the ringtones folder ?
#11 by Alan on March 3rd, 2010
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Delete the first clip you made as stated in Step 21.
#12 by Tibi on March 3rd, 2010
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PERFECT, worked like a charm :) it was succesfull for me at the 2-nd time because i just had to pay a little attention :) it works 100% just open your eyes and pay attention and do precisely what it says on every step and it works:) thank you very much this is great
#13 by Hitesh on March 3rd, 2010
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The most CLEAR instructions on the web.
So easy, even a caveman can do it!
:~))
Great job, Alan!
#14 by cathie batchelor on March 3rd, 2010
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got my ringtones in i tunes, synced iphone and all went well, but now cant find the ringtones on my phone. they are not under settings-sounds. any ideas?
#15 by Wendy on March 3rd, 2010
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Awesome ! Thank you so much !
#16 by HBiC on March 3rd, 2010
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I did all the steps and I can see it in itunes when it imports but it does not show up. Could it be because I am using the 1st gen iphone?
#17 by HBiC on March 3rd, 2010
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well I figured out that on the 1st gen you can’t have more then a 30 sec clip. ;-)
#18 by kimmy on March 4th, 2010
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thankx dude u rock
#19 by linda on March 6th, 2010
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I had follow the instructions, but how come the clip is not 30 secs long? eg. start time 1:20 and stop time is 1:50. when i create the AAC file, i play it and it start at 1:20 but last 1:50 secs…. what had i done wrongly?
#20 by Michael B. on March 6th, 2010
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I had no trouble using this proceedure. I am using iTunes 9 and iPhone v3.1.3
#21 by David on March 6th, 2010
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Um, weird, I followed the instructions, but iTunes is not letting me drag the ringtones into the Ringtones playlist! It just refuses.
I can’t get them to sync to my phone at all.
#22 by David on March 6th, 2010
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Argh – never mind previous comment! I had to go to Devices > my phone > Ringtones, and tell it to sync ringtones. No need to create the special Ringtones playlist.
#23 by Chivaz on March 7th, 2010
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it was going all good, untill i got to step 25. when i click on ‘Sync Ringtones’ its wont let mi select ’selected ringtones’
what do i do??
#24 by Drew on March 7th, 2010
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Dude…AWESOME! Took me a total of 3 minutes, PERFECT!
#25 by kedes green on March 8th, 2010
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i cant find preference on ma itunes
#26 by NOLAGurlDeeMoney on March 9th, 2010
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uuuhhh..did everythng right…now syncing is taking forever…what’s up wit that?
#27 by Unknows on March 14th, 2010
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You are Great!!!!
#28 by Unknows on March 14th, 2010
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kedes green, the ITUNE VERSION shown on pics are old, go to EDIT TAB.
#29 by meow on March 14th, 2010
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why did all my songs delete
#30 by Brooke on March 16th, 2010
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I’ve been making my own ringtones like this for years, so I get the process. Unfortunately, I think my iTunes is too smart because when I try to add the new m4r to the library, it does not work. :(
#31 by RG on March 16th, 2010
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The problem I’m having is that every time I specify the start and stop times, it seems to ignore the stop time and keeps creating a clip that’s 1 minute in length. Thus, no ringtone I create in this manner can be used or synched. I’m not sure why it’s happening.