Which Lock Or Latch Do You Need?

The choice of fittings for your door knob or door handle can be confusing. So many different sizes and options. Following our previous blog, Choosing The Right Tubular Latch, read on for a simple overview of how to choose the right lock or latch for your door.

Tubular Latch

A standard latch for opening and closing internal doors when a lock is not required. The tubular latch is designed to be fitted with either a pair of door handles or door knobs.

When fitting a door knob to a door requiring a lock, we generally advise the use of a 4 inch tubular latch, a 4 inch deadbolt and a turn & release (as shown above).

Tubular Latches are available in a range of sizes and options - please see Choosing The Right Tubular Latch for more details.


Sash Lock

A sash lock is a combination of a latch and a key operated lock contained within one case. Designed to be fitted with a pair of key lock profile handles.

Internal & External Door Sash Locks

Sash locks are designed with levers to prevent the bolt from moving into the lock. The number of levers (2-7) reflects the level of security of the lock.

3 lever locks are the most commonly used lock for all internal rooms where privacy rather than security is required, such as bedrooms.

5 & 7 lever locks have a greater level of security and are required for external doors. There is a choice of British Standard or Euro Profile cylinder locks for external doors. Some insurance companies insist upon British Standard locks for external doors, but please check with your insurance policy when making a decision before buying.


Sash Locks are available in a range of sizes. The most commonly used sizes are 2.5 inches or 3 inches and these are suitable for fitting with most lever handles.


Bathroom Lock


A bathroom sash lock is very similar to a sash lock operated with a key.

Designed to be operated by a pair of handles with a thumb turn locking mechanism. Generally intended for bathrooms, shower rooms and toilets, but can be used on any internal door where the use of a key is not required.

Not suitable for external doors.


As with the standard sash lock, bathroom sash locks are available in a range of sizes, the most popular being 2.5 inches or 3 inches.


See HERE for our range of tubular latches and sash locks.



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  • Suffolk Latch Company on May 31, 2023

    Hi Stephanie, If your door can accommodate a 4-inch latch we would always recommend that when using door knobs, however, a 3-inch latch will work just as well.

  • Stephanie Gilbert on May 31, 2023

    Hello! I live in the States and I was wondering how to figure out whether I need a 3 or 4 inch latch when ordering the locking door knobs. Thanks!

  • Sam Andrews on May 31, 2023

    I find it interesting when you suggested that tubular latches are suitable for many door knobs or handles. My basement door is getting harder to open because its lock has started to get rusty. Maybe I should get a new latch by asking a locksmith to make the right installation. https://cwtrailerlocks.com/shop/ols/products/cw2020c-cast-2-516-demco-easy-latch-lock

  • Well HardWare on Mar 16, 2022

    Thank you for your helpful article, I love this type of article.