How to Use a Door Lock With or Without a Key

With a key, insert it fully, turn it to throw or retract the deadbolt, and check that the bolt moves all the way. Without a key, you can use the inside thumb turn, a keypad code or a push button, depending on the lock type. If you are locked out, use a spare key or code, or call a locksmith or your landlord rather than forcing the door.

Using a door lock with a key

Most entry doors use a keyed deadbolt, sometimes paired with a knob or lever. The key turns a cylinder that moves a metal bolt into the door frame. That bolt, not the handle latch, is what holds the door shut against force.

Take your time the first few days. Most key trouble comes from a half-inserted key or a door that is not fully closed.

Close the door fully so it rests against the stop and the bolt lines up with the hole in the frame.
Push the key all the way into the cylinder, then pull it back a hair if it feels like it is bottoming out.
Turn the key in the direction that moves the bolt out (usually clockwise on a right-handed door, but check yours).
Keep turning until the key stops. A full turn is needed for the bolt to extend completely.
Pull the key out and give the door a gentle push to confirm it is secure.
To unlock, turn the key the other way until the bolt is fully back, then use the knob or lever to open the door.

Using a door lock without a key

Many locks are made to work without a key from at least one side. Which method you have depends on the lock. The most common ones are an inside thumb turn, a keypad and a push button.

Some locks are single-cylinder, which means a key is needed outside but a thumb turn works inside. The Estmoon set on our comparison page, for example, locks and unlocks from outside with a key and from inside with a thumb turn. That is handy because you can lock up at night without hunting for a key.

Method	How to lock	How to unlock	Good to know
Key and thumb turn	Turn the thumb turn inside, or the key outside	Turn the thumb turn inside, or the key outside	Keep a spare key somewhere safe and off the door
Keypad	Press a key or button, or let auto-lock do it	Enter your code	Needs batteries, so watch the low-battery signal
Push-button knob	Push the button on the inside knob	Turn the knob from inside	Common on bedrooms and bathrooms, not for entry doors
Fingerprint	Touch or use auto-lock	Place a registered finger	Usually has a key or emergency port as backup

How to operate a keypad lock

A keypad deadbolt replaces the key with a code. The TEEHO TE001 on our list is a good example of how these work. It supports 20 access codes, plus a one-time code that is deleted after a single use, which suits a guest or a delivery visit.

The TEEHO can lock itself after 10 to 99 seconds, though that setting is off by default. You can also lock it by pressing and holding any key on the keypad for 2 seconds. Other brands do this differently, so read the manual that comes with yours.

Keypad locks run on batteries. The TEEHO uses 4 AA batteries and shows a red light when the charge drops below 15%. Change the batteries when you see a warning, not after the lock stops responding. Many keypad models also keep a keyway or an emergency power port as a backup, so keep the key or a USB-C cable where you can reach it.

How to operate a push-button door lock

The phrase can mean two things. On interior doors, a push-button lock is usually a small button in the middle of the knob. Push it in from the inside and the knob will no longer turn from the outside. Turn the knob from inside, or close the door hard on some models, and the button pops back out.

On an entry door, a push-button lock may be a keypad where you press number buttons. In that case, follow the keypad steps above: enter your code, wait for the signal, then turn the handle or thumb turn as your model requires.

Interior push-button locks are privacy locks, not security locks. They keep a door closed for a few minutes of privacy but are not built to resist force. Most have a small hole on the outside that lets you release the lock with a thin pin or a small flat tool. This is for doors in your own home, such as a child who locked a bathroom door by accident.

If you are locked out

First, stay calm and check the simple things. Look for an unlocked window or door only if it is yours and you can get in safely. Try your spare key, a code on a keypad, or a family member who is home.

If none of that works, call a licensed locksmith. If you rent, call your landlord or property manager first. Prying, drilling or kicking a door can damage the frame and leave the door less secure afterward.

Only open a lock you own or have clear permission to open. If you find yourself locked out of someone else's property, contact the owner.

Safety and care tips

A little care keeps locks working and keeps you safe.

Never lock a door in a way that blocks an emergency exit. Everyone in the home should know how to unlock the inside quickly, ideally without a key. A thumb turn is better than a double-cylinder lock for that reason.

When you change batteries or tighten screws, use a screwdriver that fits well. If you work on a ladder or step stool to reach a high lock, make sure it is stable and have someone nearby.

Keep spare keys with someone you trust, not under the doormat.
If a key sticks, do not force it. A graphite lubricant made for locks is gentler than oil.
Check that the bolt fully extends into the frame. A bolt that scrapes may need the strike plate adjusted.
Replace keypad batteries on a schedule, and change codes after a tenant, sitter or contractor leaves.

Choosing a lock that fits how you live

If you are shopping, think about how you will use the lock every day. A keyed deadbolt is simple and has no batteries. A keypad suits households that lose keys. If you want a quick way to compare options, our best door lock page lists security grade, deadbolt, warranty and fit details side by side.

Check the security grade and make sure a deadbolt is included. Then measure your door. Many sets on that page fit doors from 1.375 to 1.75 in thick, with a backset from 2.375 to 2.75 in. Some, like the Veise fingerprint lock, list a maximum thickness of 2 in. If you want one key for several doors, look at the keyed-alike sets in our door lock comparison.

Frequently asked questions

Which way do I turn the key to lock a door?

It depends on the lock and which way the door swings. Turn the key slowly and watch the bolt. If it moves out of the door edge, you are locking.

Why does my deadbolt not fully lock?

The door may not be closed all the way, or the bolt may not line up with the hole in the frame. Check the strike plate and make sure the door is not swollen or sagging.

Can I lock a keypad door lock from the outside without a code?

Often yes. Many models lock with a button press, a touch, or an auto-lock timer. Check your manual for the exact steps.

How often should I replace keypad lock batteries?

Follow the maker's guidance and replace them as soon as the low-battery light comes on. Do not wait for the lock to fail.