If you don't have any posts in yet it's a good idea to install them first before measuring up for a gate because you may not know exactly how far apart they will be. See the Gate Posts Page for more information on what is suitable for swing gates.
Measure as per the diagram below. Always check the slope of the driveway it may not look like there is any but there usually is so it pays to check. A Laser level is very handy for getting a level line even a low cost one from a hardware store will do, otherwise a level on a straight edge (length of steel box section) or a level string line will also do.
For more accuracy measure inside the gate posts at the top and the bottom and with a spirit level measure how plumb (straight up and down) the posts are.
If you download this page and print it out you can write the measurements on the diagram below for clarity.
If the driveway drops more than 50mm you may need to consider making the bottom of the gate raked so it follows the slope of the driveway. If the top of the gate posts are at different heights you should take the lowest post and use that or if there is fencing leading up to the gate that is also on a slope then you may consider having both the top and bottom rails raked.
The next thing to consider is if the gate has room to swing open? This can be easily checked by taking your measurement of the gate opening and checking where the gate will go when open. You would use 1/2 the gate opening for double gates.
The driveway may also rise up as you enter so you should check this too. It may not look like there is any slope but it's a good idea to check anyway just to be sure. Use the same method as above to get a level line.
If the driveway rises more than 50mm then you will need to consider either setting the bottom of the gate higher to clear, use rising hinges or make the gate so it opens outwards. Outward opening gates should not open out into a public thoroughfare so the post should be placed further up the driveway.
If a driveway has a lot of drop across it unless it falls away equally as much a single gate swung from the lower end is best
