In a deadlock vs deadlatch comparison, a deadlatch is a spring-loaded latch that locks when the door closes, while a deadlock is a solid bolt that only locks when you turn the key or thumb turn. The deadlock gives stronger resistance to forced entry; the deadlatch is more convenient.
This guide shows how each one works, where it suits best and what upgrading costs in Sydney.
Key points
- A deadlatch locks itself when the door shuts; a deadlock only locks when you operate it.
- A deadlock is the stronger choice for external doors, and many people fit both on the same door.
- Installing a deadbolt in Sydney typically costs about $290 (range $170–$460).
- Exit doors should still open from inside without hunting for a key; confirm the rules for your building.
Deadlock vs deadlatch at a glance
| Feature | Deadlatch | Deadlock |
|---|---|---|
| Bolt action | Spring-loaded latch with a small guard bolt | Solid bolt with no spring |
| How it locks | Automatically when the door closes | Only when you turn the key or thumb turn |
| Resistance to forced entry | Moderate; depends on the door and frame | Higher; the bolt cannot be pushed back by pressure |
| Convenience | High; hard to forget to lock | Lower; you must lock it every time |
| Typical position | In the handle or lockset | Above the handle as a separate lock |
How deadlocks and deadlatches work
Both lock a bolt into the door frame, but they hold it in place differently.
- Deadlatch spring: a spring pushes the angled latch into the strike plate, and the guard bolt stops it being pressed back once closed.
- Deadlatch locking: the latch locks the moment the door closes, so you need a key or snib to hold it open.
- Deadlock throw: turning the key drives a square bolt deep into the frame, and it stays there until you turn it back.
- Deadlock thumb turn: inside, a thumb turn lets you unlock without a key, but check that your household can always reach it.
- Strike plate alignment: houses settle, and a misaligned plate stops either bolt seating fully, so adjust it before blaming the lock.
Where each lock is used
- Front doors: a deadlatch in the handle plus a separate deadlock above it is a common Sydney combination.
- Rental properties: a deadlatch alone is common, so landlords and tenants should check the lease before adding locks.
- Back and side doors: a deadlock suits doors that are out of sight from the street.
- Apartments and strata: fire exit rules and strata by-laws can restrict which locks you may fit, so ask your strata manager first.
- Security screen doors: a deadlock-style bolt is common on security door locks for extra strength.
Deadlock vs deadlatch specs and costs
| Item | Detail (Sydney, Oct 2026) | Why it matters |
|---|---|---|
| Deadbolt installation | AUD 170–460, typically 290 | Adds a deadlock where you only have a latch |
| Basic lock replacement | AUD 140–400, typically 255 | Worn or damaged latches are best replaced |
| Re-key, per lock | AUD 52–140, typically 75 | Stops old keys working without new hardware |
| Locksets standard | AS 4145 | Ask your locksmith which rating the lock meets |
| Locksmith licence (NSW) | Class 2C | Ask for the licence number before work starts |
Related terms
- Deadbolt: the American name for a deadlock; in Australia the terms are used interchangeably.
- Strike plate: the metal plate in the frame that receives the bolt.
- Snib: a small button that holds a deadlatch unlocked from inside.
- Sliding door lock: a hook or bolt designed for glass doors; see sliding door locks.
Deadlock vs deadlatch FAQs
Is a deadlock better than a deadlatch?
For security, yes, because the solid bolt cannot be pushed back and only unlocks with the key or thumb turn. A deadlatch is more convenient because it locks itself. Many Sydney homes use both on the front door, giving automatic locking plus extra strength when you leave or sleep.
How much does it cost to add a deadlock?
In Sydney, deadbolt installation typically costs about $290, with a range of $170–$460 (October 2026). After-hours call-outs carry a surcharge that varies by locksmith, so confirm the total price first. Booking during business hours usually keeps the bill closer to the typical figure.
Can I use a deadlock on my rental door?
Check your lease first, because changes to locks usually need the landlord’s or agent’s written consent. Exit doors should also open from inside without a key. A licensed locksmith can advise on rules for your building and fit a compliant lock.
For the wider picture, read our types of door locks guide, or book a licensed locksmith to fit or replace yours.
