How to Use a Credit Card to Unlock a Door

A credit card can be the key to more than just a good deal -- it can actually help you open a locked door. That's a good thing to know the next time your toddler mistakenly gets locked in the bathroom or bedroom or you lock yourself out of the house. This handy lock-picking technique doesn't work on all locksets, and some door jamb designs thwart it, but you still have options.

Portrait of young woman holding credit card
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If you're locked out of the house, your credit card may get you in.

How It Works

A typical door lockset has a barrel that fits through the strike on the jam, and as long as it's engaged, you can't open the door. The barrel pulls back when you turn the knob, but a typical locking mechanism physically prevents the knob from turning, although the knob remains engaged with the barrel. If you can wedge a thin and rigid -- but flexible -- item between the door and the jamb and push it against the barrel, there's a good chance that it will slip over the end of the barrel when you jiggle the knob. Once that happens, it's a simple matter to push the barrel back and open the door.

Door and Jamb Requirements

The plastic card technique doesn't work on every door and with every lockset. The handle of an electronic lockset with a keyed entry pad disengages from the barrel when the door is locked. Because of this, you can't jiggle the barrel and create a gap large enough for a credit card between the end of the barrel and jamb. The card trick also won't work if the door has a stop mounted on the outside jamb that covers the gap through which you need to insert the card. For the trick to work, you have to be able to see the edge of the door.

How to Do the Card Trick

The procedure for opening a door with a plastic card isn't complicated, and it takes only a few seconds. Use a card that you don't mind damaging. Insert the card into the gap between the door and the jamb and slide it down until it contacts the barrel. Keep downward pressure on the card while you jiggle the handle, and at some point, you'll feel it move down a little farther. When this happens, wedge the card against the knob to keep tension on it and keep jiggling the knob, and the door should open.

Opening a Door With a Stop

Because it remains disengaged from the barrel while it's locked, an electronic lockset is virtually impossible to open with a plastic card. If your door has a stop that's in the way of the card, though, you may still be able to unlock it in an emergency, but you'll need a flat-head screwdriver. Use the screwdriver to pry the stop out far enough for you to slip the car behind it and open the door. Once the door is open, pound the nails holding the stop back in, using a nail set; then fill the nail holes with wood filler and touch up the paint.