Unless you have built-in precautions against this, you can straighten out a wire hanger and insert it through the top of the garage door. Feel around until you reach the emergency latch. If you can hook the cord, slowly pull on it. Once the safety release is disengaged, you can roll the door up manually.
If your door is a manual door and doesn't have a motorised opener, then yes: you can very easily open the door from the inside and the outside. If the door is locked, however, and you're on the outside of it, you're going to have some trouble opening it.
To open a garage door from the outside, use the emergency release key to open the emergency release lock. Then, pull the cord down to unlock the door. Use the same key to unlock the manual lock (near the center of the garage door), then turn the handle vertical. Finally, lift the door up from the bottom to open it up.
Call a Locksmith
If you locked the door manually and didn't re-engage the electric opener, you may not be able to get back inside. There may also be damage to the system. You could always call a locksmith to repair or replace the manual lock and/or provide you with a new key if one is broken or lost.
There should be a handle somewhere on the inside of the garage door. Grab it and lift upward. With the door disconnected from the opening mechanism, it should be relatively easy for one person to raise the door to the fully open position.
During the fall and winter seasons, high winds and heavy rains can cause debris and dust to blow around and accumulate at the threshold of your garage door. If your garage door is not able to make a good seal and close all the way, it could be prompted to spontaneously open, as part of the safety mechanisms built in.
A burglar can open a garage door from the outside in a matter of seconds with nothing more than a wire coat hanger. All they have to do is use a tool to pry open the top edge of the door, drive the hanger through the opening, grab the cord with the hook and pull.
A double-skinned roller garage door provides extra protection against forced entry. Make sure the bottom slat is strong and durable, as this is where most thieves will try to breach your garage door. You can also invest in extra locks and bolts, making it harder for burglars to dislodge the door.
If your garage door has a broken cable or spring, opening it manually is going to be quite difficult and potentially dangerous. We recommend contacting a garage door repair professional because if a spring is broken the door is going to be very heavy to lift.
We recommend not attempting to open your garage door if it has a broken spring. Follow these safety tips if you must open the door to get a car out: Keep yourself safe by protecting your back, keeping your fingers away from pinch points and ensuring your feet aren't under the door.