Most side gates are between 900mm and 1 metre wide. That width lets one person walk through with shopping, wheel a bin out, push a mower or a pram, and get a wheelbarrow into the backyard without turning sideways. Those everyday jobs are what a side gate is for, which is why 900mm has become the default. The right width for your place comes down to three things: how wide your opening is, what you need to move through it, and whether the gate swings or slides.
Here is how to land on the right size.
The standard side gate width, and why 900mm is the default
A 900mm gate clears a standard wheelie bin with room to spare, takes a ride-on or push mower, and is wide enough for a pram or a person carrying boxes. Drop below about 820mm and it starts to feel tight every time you use it. Most off-the-shelf gates are built to roughly 900mm for exactly this reason, so if you have a typical suburban side access, this is your starting point.
If your gate is the only way to get bulky gear into the yard, a trailer, a boat, a trade ute load, then you are no longer looking at a side gate. You want a wider single or double gate, covered further down.
How to measure your opening properly
This is where most people get caught out, so measure before you decide anything.
Measure the clear opening, post face to post face, or wall to fence. Do not measure your old gate, because it may have been the wrong size to begin with.
Your gate leaf is always smaller than the opening. You need to allow a hinge gap on one side and a latch gap on the other, usually around 10mm to 15mm each. So a 1 metre opening takes a gate around 970mm to 980mm wide, not a full metre.
Measure at the top and the bottom of the opening. Walls and fences are rarely perfectly parallel, and on a sloped block the gap can change from one end to the other.
Check your swing clearance. A gate that swings outward needs clear ground through its whole arc. Watch for the things that trip people up: a downpipe, an electrical or meter box, an air-conditioning unit, a step, or a slope that the gate will catch on as it opens. If the path is blocked one way, the gate needs to swing the other way, or slide, which we cover in which way a side gate should swing.
One more for anyone with a dog or young kids: it is not just the gate width that matters, it is the gaps. A gate sized too small for its opening leaves a gap at the hinge or latch side that a small dog or a determined toddler will find, and the same gap is a security weak point someone can reach through to the latch. A made-to-measure gate closes those gaps off.
How tall should a side gate be?
The standard side gate height is 1.8 metres. That matches most Colorbond and timber fences, keeps the yard private, and is tall enough to stop someone simply stepping over it.
If the gate forms part of a pool barrier, it must be a minimum of 1.2 metres and meet Queensland pool safety rules, which means self-closing, self-latching, and a latch at the right height. That is a separate topic worth getting right before you buy.
You can go taller than 1.8 metres for extra privacy or security, but height adds weight, and weight on a single swing gate means more strain on the hinges and posts over time. Past a certain point you are better off with a heavier-duty frame or a sliding setup.
What if your opening is wider than a metre?
This is where off-the-shelf runs out. Prefab gates generally stop at around 1.6 metres, so anyone with a wider opening ends up either splitting it into two small gates that do not quite suit the space, or going custom.
Here is the simple rule:
- Single swing gate: practical up to about 1.5 metres. Wider than that on one leaf and the gate starts to sag and drags on the hinges, especially in timber.
- Double swing gate: two leaves meeting in the middle, ideal for openings from roughly 3 to 5 metres.
- Sliding gate: the best option for wide openings, or anywhere there is no room for a gate to swing into. It needs clear run-back space alongside the opening for the gate to slide into.
Aluminium gate sizes for driveways
For driveway gates the same logic applies, scaled up. Aluminium has a real advantage here: it is far lighter than steel, so a wider leaf sags less, sits truer over the years, and puts less load on an automatic gate motor, which helps the whole system last longer. (More on that in our guide to how heavy aluminium gates are.)
As a rough guide:
- Up to around 3 metres: a double swing gate, or a single sliding gate.
- 3 to 5 metres: double swing or sliding, depending on swing room.
- 5 metres and wider: sliding is usually the cleaner answer.
The exact size depends on your slope, your fall, and how much room you have to either side, which is why these are best measured on site.
Why a made-to-measure gate beats an off-the-shelf size
A gate built to a standard size has to be forced to fit a non-standard opening, and most openings are non-standard. That is how you end up with oversized gaps, a gate that scrapes on a slope, or two narrow gates doing the job of one.
Every gate we build is fabricated in-house to the exact measurements of your opening, square or sloped, narrow side access or wide driveway. That means a clean fit with no gaps for a pet or a child to slip through, a finish powder-coated to match your fence colour, and a gate that actually suits your block instead of one you have settled for. Most projects are designed, made and installed in 5 to 10 days, and an aluminium gate stays looking new with next to no maintenance.
If you are not sure what size suits your opening, send us your measurements or a few photos for a quote and we will tell you what fits.