Blog
How to Measure Your Door for a Digital Lock (Main Door, Grille and Frame Door)
The most common reason a digital lock installation goes wrong is not the lock. It is a lock that was never right for the door. Five minutes with a measuring tape and your phone camera avoids that. Here is exactly what to check, door by door.
What you need
- A measuring tape or ruler (millimetres)
- Your phone camera
- Five minutes with the door open
1. Door thickness
Open the door and measure across its edge, from the outside face to the inside face. This is the single most important number:
| Door type | Typical thickness | Avant Guard series |
|---|---|---|
| Wooden, fire-rated or metal main door | 40–120 mm | Door Lever, Push Pull, Signature |
| Room door | 35–100 mm | Handle & Rim |
| Grille door with lock case | 25–100 mm | Grille Door (G12, G22 V2) |
| Grille frame without lock case | 25–50 mm | Grille rim locks (G45, G40) |
| Frame or mesh door | 25–100 mm | Frame Door |
2. What lock is there now?
Look at the edge of the door where the latch comes out:
- A long metal plate with a latch and a deadbolt means you have a mortise lock. Most digital locks replace this directly, often reusing the same cut-out. Photograph the plate straight on with a tape measure beside it, showing its height and width.
- A small round latch with a knob means a cylindrical (tubular) lock. The door will need a new mortise cut; your installer handles this.
- A surface-mounted box (common on grilles) means a rim lock. You may need a rim-type digital lock.
3. Door material and condition
Note whether the door is solid timber, fire-rated, hollow-core, metal or glass. Hollow-core doors are too weak for a main-door lock. Glass doors need a dedicated glass-door lock, such as our office-series locks or an EM lock. Check that the door closes smoothly without dragging; a misaligned door makes any motorised lock work harder and drains the battery.
4. Gaps
- Door to frame gap: the space between the closed door and the frame on the lock side. Too large a gap leaves the bolt only partly engaged.
- Main door to grille gap: if you have a grille outside your main door, measure the space between them when both are closed. The main door lock’s outer panel and handle must fit in this space.
5. Opening direction
Note whether the door opens inwards or outwards, and whether the hinges are on the left or right when you stand outside. Some locks, such as hotel locks, come in left- and right-handed versions.
6. The photos to send us
- The whole door from outside
- The whole door from inside
- The door edge and lock plate, with a tape measure beside it
- The door thickness, with the tape across the edge
- If you have a grille: both grille and main door closed, from the side
WhatsApp these to 014-338 6654 and we will confirm which models fit, then arrange installation at a time that suits you.
Detailed guides by door type
Once you know your door, use our digital door lock buyer’s guide to pick the features.
Frequently asked questions
What door thickness do digital locks fit?
Most main-door digital locks fit doors 40 to 120 mm thick. Grille locks fit about 25 to 100 mm, and rim-type grille locks about 25 to 50 mm.
Can I install a digital lock on a hollow door?
Hollow-core doors are not strong enough for a main-door lock. Use a solid timber, fire-rated or metal door.
Will the installer need to cut my door?
If you already have a mortise lock, the digital lock often reuses the existing cut-out with minor adjustment. A door with a small round tubular lock needs a new mortise cut, which the installer does.
Can you check my door before I buy?
Yes. WhatsApp photos of your door, the lock edge and the thickness to 014-338 6654 and we will confirm which models fit.
See it before you buy. Try every lock and light at our showroom in SPHERE Damansara, Petaling Jaya (Mon–Fri 9am–6pm, Sat–Sun 10am–5pm), or WhatsApp us a photo of your door at 014-338 6654 and we will recommend the right model.