How To Open A Locked Interior Door When You’ve Lost The Key

How To Open A Locked Interior Door When You’ve Lost The Key

If you have a lot of interior doorknobs with key locks on them, sooner or later you’re bound to lose the key or lock them inside the room. Here’s what to do to get back in.

When one of my interior doors got locked with the keys inside recently, I learned all I ever wanted to know about lock-picking and doorknob assembly. Locksmiths are expensive, so let me share everything I tried and show you how I eventually got the door open.

If the doorknob in question is a simple push-button affair, most of the time all you need to do is jab a paperclip in the hole and push on the locking mechanism. If the doorknob just has a slit on the outside handle, a butter knife should do the trick.

Keyed locks are a bit trickier to open but it can be done. The easiest approach is to grab a paperclip and tension wrench. If you don’t have a tension wrench handy, a very small hex key (roughly the same diameter as the paperclip) will do in a pinch. Take a hammer and flatten the end of the paperclip as flat as you can get it, then grab your makeshift lock-picking tools and head to the door. eHow explains what to do next:

Insert the flattened end of the paperclip above the tension wrench. Push it in until you meet resistance. This is the first pin of the lock. Push up on the pin with the paperclip to try and move it out of the way. When it works, the tension wrench will turn a little further. Hold the wrench in this position, still applying pressure so the pin doesn’t drop back down.

Take the paperclip out and push it back in again. When you meet the resistance of the next pin, push up on it as well until it moves and the tension wrench turns. Repeat this procedure with the rest of the pins until the lock opens.

Some lever-type doorknobs respond nicely to the credit card treatment and let you pretend you’re a secret agent while you get the door open. wikiHow says just slide the card into the crack in the door, right where the lock is.

Tilt the card so the side that’s closest to you is almost or is touching the doorknob. Push it until you feel it slide in more. Bend the card the opposite way, forcing the lock to go back. Quickly open the door. It is a good idea to lean against the door while doing this, which will help it to pop open.

If you want to go all Macgyver on the locked door, grab a vacuum cleaner, dental floss, and a piece of paper. Use the step-by-step guide over at Instructables to show that locked door who’s boss.

Sometimes, no matter what you do, the lock just won’t budge. In that event, it’s time to just remove the entire assembly. Slide a butter knife under the collar where the doorknob meets the door and pop the collar loose so you can get at the screws holding the doorknob together. Once the screws are removed, the doorknob will come apart and you’ll be able to easily slide back the mechanism holding the door closed.

If all else fails, there’s nothing a hammer wont fix. First, give the doorknob itself several good poundings until it’s good and dented. This does absolutely nothing to help unlock the door but it’s a great way to get back at the lock that’s giving you so much trouble.

Next, insert the claw end of the hammer underneath the top of the doorknob’s collar. Put a stiff piece of cardboard where the hammer meets the door to protect the paint. Cover the knob with a thick towel in case metal parts go flying, then yank the hammer down hard. Do this a couple of times until the screws holding the doorknob together snap.

When you go to the hardware store to buy a new locking doorknob, be sure to have some spare keys made while you’re there.

How to Open a Locked Door With a Paperclip [eHow]

How to Open a Door With a Credit Card [wikiHow]

How to Open a Locked Door the Macgyver Way [Instructables]


  • I had this problem recently.

    There is usually ( on wooden door frames) a strip of timber that blocks access to the tongue of the door. This is commonly nailed in.

    I used a metal ruler to gently pry this slightly away from the frame and then kept pushing until it pushed the tongue back enough to open the door.


    If you can see the tongue, you can use two knives. One from above and one from below. Use one to slide the tongue in. It probably wont go far enough to open the door, so use the second knife to hold it in place while you repeat with the first knife. Butter knives work, but I prefer steak knives – the serrated edge grips the tongue better.

    And before you ask, I dont do this for a living! I am constantly locking my keys in my office at work.

    Hope this helps someone.

  • Yanking a knob off a bedroom door with a claw hammer is downright stupid. Which is more expensive: a locksmith callout, or a new door fitted to the doorway and a new lock fitted?
    That method may work on simple tie-bolt setups with weak screws, but not all bedrooms are like that. Do that with a hollow-core door and you’ll put the hammer through it faster than you’ll pull the knob off.

    Don’t use credit-cards to shim a door, use a section of a milk bottle or an icecream container.

    I am a locksmith, and I’ve seen some really stupid things done by people who’ve thought they could just hack and slash at a bedroom door to open it.
    Seriously, call a professional if you’re not absolutely positive about what you’re doing.

    If you’ve got a keyed lock on your bedroom or inside the house, either remove and replace it with a Privacy Set (like your toilet\bathroom), or remove it and take it to a locksmith, get them to rekey it the same as your house entry door key.

  • I tried all the other options and none worked – I was reluctant to try the hammer option after the locksmiths comment above, but it worked a treat. I wanted to post this for others who are reluctant. It was very simple, did no damage to the door and was WAY cheaper than getting a locksmith – especially as this happened on a Saturday night. We will obviously need to buy a new door handle now – this time one without a lock on it!

  • Yes, this is clever. But if you make a little mistake you could end up damaging the door. I am really particular about things, but trying to break open a lock I have inflicted damage to the door, I therefore suggest locksmith is a wise solution.

  • I usually do not “join the discussion” BUT after my spare key failing me access to my spare room I had to comment. I simply googled “how to break into my bedroom” 🙂 and WHALAH here I am. I didn’t understand all of the “tension wrench” talk so I decided to go with what I KNEW probably WOULDNT work…. Yup, the credit card method. But it did!!! WoW!!! I’m a BELIEVER.

  • I had to join in on this conversation. Unfortunately yes, i locked myself out my room this evening, and googled how to unlock my bedroom door. Never broke into any door, never had to until now. So I tryed the credit card method, took me less then a minute. I even have the wood wedge frame in front, making it a bit difficult. you Just have to start at the top and work ur way to the lock. I actually spent more time reading this nonsense on the locksmith saying what not to do. Of course he would say to call a professional. So YES, the credit card theory DOES work.

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