What's inside
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What the job requires
Hanging an interior door is mostly measuring, fitting and removing small amounts of wood. The essential kit is modest: a tape measure, pencil, straightedge, sharp chisel, hammer, drill or screwdriver, and a way to support the door while you work. A hand plane is useful for trimming an edge, but it is not essential if the door fits already.
Before buying tools, check what kind of job you have. Replacing a door in an existing frame is different from installing a new frame, and a door that is badly warped or an opening that is out of square may need more than careful hinge fitting. Take the door’s width, height and thickness, and note the hinge positions on the old door if it is available. Don’t assume the new door is the same size just because it is sold as a replacement.
Measuring and marking tools
A 5 m (16 ft) tape measure is plenty for an interior door. A tape with a clear, stiff blade is easier to use alone, but an inexpensive one is fine if its hook is not bent and the blade reads accurately. Check it against a ruler before relying on it for hinge spacing. A carpenter’s pencil or a fine mechanical pencil makes a cleaner mark than a thick carpenter’s pencil when laying out hinge mortises.
A combination square is handy for transferring hinge positions and checking that marks run square across the door edge. A straightedge or long level helps spot a bowed edge or frame jamb. A 600 mm (24 in) level is convenient for a door jamb; a longer level gives a better check of the whole height. A level won’t tell you whether the frame is square by itself, so also check the opening diagonals. If they differ noticeably, fitting the door may require uneven gaps.
For occasional home repairs, a basic metal combination square and an inexpensive level are usually adequate. A more rigid square is worth paying for if you use it often; a loose or out-of-square tool can turn a careful layout into a crooked hinge.
Cutting hinge mortises
Use a sharp bevel-edge bench chisel, typically 19 mm (¾ in), for the hinge recesses. A 25 mm (1 in) chisel is useful for wider hinges, while a narrower chisel can pare corners and clean up the ends. If buying only one, a 19 mm chisel is a versatile starting size. A ¾-inch bevel-edge bench chisel is a practical choice; it need not be a premium cabinetmaking tool, but it should hold an edge and have a handle suited to light mallet taps.
Mark the hinge outline with a sharp knife or pencil, then score the line lightly with the chisel. Work across the grain in shallow cuts, keeping the bevel toward the waste, and pare down to the hinge thickness. The hinge leaf should sit flush with the door edge, not proud and not buried. A recess that is too deep pulls the door tight against the jamb; one that is too shallow can leave the hinge binding or the door standing off the frame.
A small wooden or rubber mallet gives better control than a heavy framing hammer. A hammer will work if used gently, but hard blows can split a thin door edge or drive the chisel past the line. Keep the cutting edge sharp: a dull chisel needs more force and is more likely to slip. Clamp the door securely on padded supports before cutting. Never hold the door in one hand while paring with the other.
Trimming and fitting the door
A sharp hand plane can remove a controlled shaving from a door edge. A block plane is compact and useful for easing a corner; a longer bench plane tracks more steadily along a long edge. For fitting a door, the longer plane is less likely to create a hollow, but a sharp block plane is enough for small adjustments. See hand planes for door fitting if you need to compare sizes.
Plane only after confirming where the door is tight. Mark the high spot, remove a little, and test the fit again. A gap of roughly 2 mm (about 1/16 in) along the sides and top is a common target, though the existing frame and door manufacturer’s guidance take precedence. The bottom gap depends on flooring and ventilation needs; check before cutting. If the door is hollow-core, read its trimming limits first. Cutting too much can expose the hollow interior or weaken the bottom rail.
For a small adjustment, sandpaper on a flat block may be slower but gives a beginner more control. A belt sander removes wood quickly and can ruin an edge in seconds; it is a poor choice unless you are experienced and can control it. If you must take off a substantial amount, check the door and frame for a deeper problem rather than removing wood blindly.
Fasteners and door support
A hand screwdriver gives good control when tightening hinge screws, especially near a finished surface. A drill with a clutch is faster for pilot holes, but use a small bit and stop before driving screws fully home. Overdriving can strip the hole, split the jamb or leave a screw head damaged. If a hinge screw spins without tightening, the hole may need a repair rather than a larger screw forced into it.
Support the door at hinge height while fitting it. A helper is the simplest option; otherwise use stable padded supports or wedges that hold the door without rocking. A door slipping off a support can damage the floor, the edge or your fingers. Keep the work area clear and don’t balance the door upright unattended.
What to buy first
| Tool | Best use | Budget trade-off |
|---|---|---|
| Tape measure and pencil | Measuring the door and laying out hinge positions | Cheap is fine if the tape is accurate and the hook is sound. |
| Combination square | Marking square hinge lines and checking short edges | A basic square works; avoid one with a loose head. |
| 19 mm bench chisel | Cutting and paring hinge mortises | A modest chisel is adequate if sharp; a dull bargain tool costs time. |
| Hand plane | Shaving a tight door edge | Not needed if the door fits. A sharp, simple plane beats a fancy dull one. |
| Mallet and supports | Controlled chisel work and safe fitting | A light mallet and padded, stable supports are sufficient. |
For carrying the kit between jobs, a small carpenter tool belt or tool pouch keeps the tape, pencil, square and screwdriver close. It is optional for a single door, and a bench or tray is just as useful indoors. A compact site kit should also include spare hinge screws, a small drill bit for pilot holes, and a sharpener or honing stone for the chisel and plane iron. A clean cut and a controlled fit depend more on sharp edges and accurate marks than on owning a large collection of tools.