To replace or update garage doors, proper measurement is crucial. Furthermore, garage door measurements will help you calculate your garage’s clearance level—in other words, you’ll know the maximum-sized vehicle that you can pull into the space. Adequate measurement consists of recording more than simple side-to-side and top-to-bottom dimensions. Luckily, proper measurement is relatively simple and can be achieved by two people in just a few minutes, with just a simple tape measure and step ladder.


    1: Use a tape measure to measure the Garage Door’s opening from side to side near the floor of the garage. Measuring large dimensions of a Garage Door can be very tricky for one person. Ask a friend to help you hold one end of the measuring tape. Record this first measurement and all subsequent measurements on a piece of paper.

    2: Measure the door’s opening from side to side again, this time near the topmost part of the Garage opening. Measuring both top and bottom width-wise dimensions will let you know if the door warped—if you get two differing dimensions at each point, then your door’s opening is slanted or bent, and you should hire a contractor to fix the problem.

    3/4: Stand on a stepladder and measure the Garage Door’s opening from top to bottom. For this measurement, you can take advantage of gravity, letting the tape measure fall to the ground for easy measurement. However, you’ll still want a friend handy to hold the stepladder for safety purposes. With this lengthwise measurement and your previous width-wise measurements, you’ll know how large the opening is for vehicle and door replacement purposes. However, additional measurements are also useful.

    Once you have worked out the area, the gap now needs to be reduced to allow for opening clearances. These are as follows:

    Reduce Width by 30mm (1 1/4″) – allows 10mm per side and also 10mm for centre
    Reduce Height by 35mm (1 1/2″) – allows 10mm at top and 25mm at bottom

    If you are putting in a new frame, please remember to also reduce this off your opening gap. For more info, please call for advice.