First thing first: Make sure you’re using the right key. If it’s the correct key for your lock, there are a few reasons why it may not be working, like the key is worn out or the lock is jammed. Try lubricating the lock and pushing the door closed to ensure the mechanisms work correctly. If you’re still locked out, call in for help.

A door lock service is performed by a professional locksmith, and the cost of hiring a locksmith for these kinds of repair tasks usually runs in the $100 to $250 range. It all depends on the type of locks you have, how many locks are included in the service, and where your home is located. Always choose reliable, trustworthy locksmiths, and get a few quotes before making your choice. 

Most door knobs can be removed with a Phillips or flathead screwdriver. If you don’t have either of those available, a paper clip or small pin can sometimes work, but the extra effort may not be worth a quick trip to the hardware store.

Expect to pay between $50 to $200 if you hire a locksmith to change your locks. That figure includes labor and the cost of basic hardware. The cost will naturally be higher if you plan to install more expensive locks, like smart locks, and if you need a lot of them.

Homeowners can save money by replacing locks themselves. A typical rekeying kit costs about $10 to $25. The only additional cost is purchasing new house keys, and those are no more than a few dollars per key. If you want to replace the locks on your own completely, the main cost is the price of the locks themselves. A standard knob-style lock starts around $25, while electronic locks and smart locks will run in the hundreds of dollars. The only additional tools you should need are a tape measure, screwdriver, and screws if they are not already provided.