The complete guide
Door Butt Hinges, A Practical Buyer's Guide
The problem nobody notices until it annoys them
Doors fail quietly. One day the bedroom door brushes the carpet on the way shut. Another day it drifts open while you are trying to sleep. Then there is the squeak, the one that only appears at two in the morning when somebody gets up for water.
Almost every one of these problems traces back to the same small piece of metal. Hinges carry the entire weight of a door, every single day, through thousands of open and close cycles. Over the years the knuckles wear, the pin develops play, and the screws slowly chew out their holes in the timber. The door drops a few millimetres. That is enough to make it scrape, stick, or swing on its own.
The good news is that this is one of the cheapest, most satisfying repairs in a house. New hinges, a screwdriver, and an hour or two. No trade callout needed for most interior doors.
What a butt hinge actually is
A butt hinge is two flat metal plates, called leaves, joined along one edge by a knuckle with a pin running through it. One leaf screws into a shallow recess cut into the edge of the door. The other screws into a matching recess in the door frame. When the door closes, the two leaves fold together and sit almost flush, which is why the gap between door and frame stays tight.
The name comes from the fact that the two leaves butt against each other. It is the default hinge for interior doors across most of the world, and it has barely changed in design for a very long time, because it works.
These particular hinges measure 8.9 cm by 8.9 cm, which you will often see written as 3.5 inches by 3.5 inches. That is the size used on a large share of standard interior doors. They are made from alloy steel, finished in matte black, with six screw holes per hinge.
Rounded corners versus square corners
This is the detail that catches people out, and it is worth getting right before you order anything.
When a door is made in a factory, the hinge recesses are usually cut with a router. A router bit is round, so it leaves a recess with curved corners. A hinge with rounded corners drops straight into that shape, no adjustment needed.
When a hinge recess is cut by hand with a chisel, the corners end up square. A rounded hinge in a square recess leaves small gaps at the corners. A square hinge in a rounded recess will not sit down at all until you pare the corners out.
So before you buy, take one hinge off a door and look at it. Round corners, rounded hinge. Square corners, square hinge. It takes thirty seconds and it saves a return. These hinges are the rounded type, which matches most factory-made doors.
Why eighteen in a pack is a sensible number
Buying hinges one at a time is a trap. Finishes vary between production batches, and a matte black from one run can sit slightly warmer or cooler than another. Hang two doors opposite each other in a hallway with hinges from different packs and you may notice it. Visitors will not, but you will.
Eighteen hinges covers six doors at three hinges each, or nine doors at two each. For a typical three bedroom home, that is most of the interior doors in a single order from a single batch. The finish matches throughout, and you have a consistent look right down the hall.
There is also the half-used-pack benefit. Spare hinges are handy. A stripped screw hole on a cupboard door, a shed door that needs rehanging, a flat pack wardrobe that came short. Having a few in the drawer is better than a trip to the hardware shop.
Two hinges or three?
A short, light door can get by on two hinges. Most standard interior doors are better on three. A tall or heavy solid door sometimes wants four.
The reason is simple. Three hinges spread the load so no single fixing takes the whole weight, and the middle hinge helps stop a door bowing away from the frame over time. If your doors already have three, replace all three. If they only have two and the door has started to sag, adding a third while you are at it is a small amount of extra work for a noticeably better result.
A word on screws. The pack includes mounting hardware, but on any door that feels heavy, a lot of fitters swap one screw in each frame leaf for a longer one that reaches through the frame into the stud behind. That single change does more for a sagging door than almost anything else. Screw length supplied with this pack is not stated in the product record, so check what arrives.
Fitting them without drama
For a straight replacement, the job is genuinely simple.
Prop the door so it cannot move. A wedge under the bottom edge, or a helper holding it, both work. Undo the screws on one hinge only, leaving the other hinges doing their job. Lift the old hinge out, drop the new one in, and drive the screws. Then move to the next hinge, and the last.
Two things to watch. First, go easy on the drill. High torque strips screw heads and spins screws past their seat into soft timber. Start the screw with a drill on low, finish by hand. Second, if an old screw hole is chewed out and the screw just spins, do not force it. Glue a couple of hardwood slivers or a matchstick into the hole, let it set, then drive the screw into fresh timber. Thirty minutes of waiting saves a hinge that never holds.
If the door still sits slightly wrong once everything is tight, a thin cardboard shim behind one hinge leaf will shift the door a millimetre or two. That is the old trick for a door that catches on one side.
Matching the rest of your hardware
Matte black has become the default for a lot of modern interior schemes, and it carries well in older homes too. The reason it works is that it reads as deliberate. Flat black beside a white painted door gives a clean dark line down the hinge edge, and it ties in with black lever handles, latch plates, door stops and hooks.
Practically, matte finishes also hide fingerprints and light scuffing better than polished ones. Nobody touches a hinge often, but the door edge next to it collects marks, and a flat finish blends in rather than drawing the eye.
If your handles are brass or chrome, you have a choice to make. Some people like the contrast of black hinges against brighter handles, others prefer everything matched. There is no rule here. Just decide before you buy, rather than after.
Keeping them working
Hinges ask for almost nothing. Wipe them when you clean the door, using a dry or barely damp cloth, and dry them off. Skip abrasive pads and solvent cleaners, which can mark a finish.
Once a year, run a screwdriver over the screws and snug up anything loose. Screws work free with vibration and seasonal timber movement, and catching a loose one early stops the hole wearing out.
If a squeak appears, a small amount of light machine oil or a dry lubricant at the knuckle usually ends it. Apply sparingly and wipe the excess so it does not run down a painted door.
What this record does and does not tell you
Being straight about the gaps matters. This listing confirms the size, the material as alloy steel, the matte black finish, the six screw holes, the rounded corners, the 18 piece pack and the included screws and instructions. The stated item weight is 168 g.
The maker does not list leaf thickness, pin type (removable or fixed), load rating, warranty terms, or country of origin. If any of those are make-or-break for your job, particularly on a heavy or external door, confirm before ordering rather than assuming.
The short version
If you have standard interior doors with rounded factory-cut mortises and you want them to shut quietly and hang square again, this is a straightforward fix. Measure one existing hinge, check the corner shape, count your doors, and order.
Replace all the hinges on a door at the same time. Use three per door where you can. Go gentle with the drill, plug any stripped holes properly, and keep a couple of spares in a drawer.
It is a small job with a disproportionate payoff. A door that closes with one clean click instead of a scrape and a shove improves a house more than its price suggests.