Things You'll Need
Screwdrivers — Philips and flat
Home repair store
It’s less expensive to re-key your existing locks than to completely replace every exterior door lock, but both are options.
Consider having each door re-fitted to work with a different key. For example, you can retool the backyard door to open with a different key than the front door uses. This option could reduce future lockout and security issues.
If losing keys is an unfortunate habit, consider installing key code or electronic key-less entry locks instead of standard locks.
Make sure someone reliable stays at your house to prevent any intruders while you go to the store to re-key the lock.
Any door lock that uses the same missing key should be re-keyed or replaced.
Losing keys can be a frustrating experience, especially if there are no spares inside or neighbors with a spare. It can also be a matter of security to find the best and most efficient way to replace a lost house key to ensure the missing key doesn't fall into the hands of criminals. Therefore, make quick work of choosing one of these methods to resolve your missing key issue and keep your home safe and secure.
Unlock the door from the inside. If it has a deadbolt and a handle lock, move both of them to the open or unlocked position before removing the doorknob.
Remove the doorknob by unscrewing the bolts or screws on the lock, usually located on one side of the door but not the other. First unscrew the bolts that hold the doorknob to the face of the door. If necessary, also remove the doorjamb plate that holds the locking mechanism in place. If you have a deadbolt lock and handle lock that use the same key, remove both of them.
Take your doorknob and/or deadbolt to a locksmith or hardware store that makes keys. Ask for the service of "re-keying" the lock. This will allow you to use the same doorknob hardware, but makes the lost key useless in this re-keyed lock.
Hire a locksmith to do a house call and re-key your locks if you have several door locks that all operate with the missing key.
Make at least three copies of the new key. Keep one on your key ring, give one to a trustworthy friend or neighbor and leave one hidden in your car or in an outside safe location that only you know.