How to Reformat Your SIM Card

By Louise Balle

A cell phone's SIM (subscriber identity module) card is designed to hold basic information, including contact lists, text messages and sometimes calendar entries. When it's time to sell or donate your cell phone or if you just want to wipe your card clean, you'll have to reformat it, which means you will delete the card's memory and start fresh.

Things You'll Need

  • SIM card code (specific to each phone model)
  • SIM card reader (optional)

Step 1

Find the data reset commands for your specific cell phone model by using the Cell Phone Data Eraser on the Wireless Recycling website at (or a similar service). These types of websites issue instructions for just about all phone models for free or a fee. Enter the cell phone model, register with the service and retrieve the PDF file that is sent to your email account. You will find reset instructions for your cell phone model in this PDF file.

Step 2

Follow the unique instructions for your cell phone. The code, which is found in the PDF file, is a series of keystrokes specific to that cell phone model and it will reformat the SIM card.

Step 3

Turn off the cell phone, then restart it. Go to your address book and choose the option to display SIM contacts. If your address book is clear, then you know that your SIM card has been properly reformatted. Also, check your organizer and other features to make sure they are cleared as well.

Tips & Warnings

  • Cell phone SIM cards are usually protected with a pin called a "PUK" code. Call your cell phone provider or check your cell phone manual for the PUK number if requested by your device when reformatting your SIM card.
  • Use a SIM card reader to delete all of the information on your SIM card as an alternative if you have data stored on your device that you want to save. The SIM reader is a USB-ready device that comes with software for your computer. Insert the card, install and load the software, and then choose the option to delete your data on the software program's main menu.
  • Keep in mind that this method will delete any contact or organizer data that is stored on the device itself as well.