How long does it take to erase all content and settings?

Sorry but it does not. Maybe 5 minutes.

 

I have a lot of data and the last time I did it, it took about 10-20 minutes.

I had a progress bar, though.

 

My original phone used to take 2 min on 2.0, now it takes 10-15 min on 3.1.3. My 4 takes around 1 min (same for every update I've gone through)

same here. sounds like OP's phone may be stuck in a loop. try forcing recovery mode http://support.apple.com/kb/HT1808

 

iPhone 2G/3G
iPod Touch 1G/2G

Do not have hardware encryption so it can takes 1-4 hours. Newer models take minutes

http://support.apple.com/kb/ht2110

 

If you chose "Erase All Content And Settings" than the Apple logo is all you're going to see.

The phone will need to be restored through iTunes to be used again.

 

Mine just took a couple of minutes.

 

how long to erase data iphone 32gb

i went to settings, clicked "erase all data and reset phone" on my 32gb iphone 4
running ios 5.1
i have had the spinning wheel for about 30 minutes now. should i wait longer or do a hard reset? is it frozen or just taking its time to erase all 32gb of data?

 

Nope.
Not since iOS 5.
You'll get the Apple logo and then go straight to the Welcome screen where you can connect to a wireless network and restore form iCloud.
No iTunes needed.

 

i remember back in the old days on my 3gs, if i "erased all content settings" or whatever, it would cause an apple bootloop/load forever -_- hopefully you didnt mess it up

 

http://support.apple.com/kb/HT2110