Which Lock or Latch Do You Need? A Practical Guide

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Choose a latch when a door only needs to remain closed, a bathroom privacy mechanism when it needs to lock from inside and appropriately specified security hardware for an external entrance door.

The handle or door knob operates the mechanism but is not necessarily supplied with it. This guide explains which locks, latches, cylinders, knobs and privacy controls work together and what to check before ordering.

Table of Contents

• Which Lock or Latch Suits Your Door?
• Tubular Latches
• Bathroom Privacy Options
• Sash Locks
• Mortice Deadlocks
• Euro-Profile Locks and Cylinders
• Night Latches
• Rim Locks
• Cabinet Latches
• Checks Before Ordering
• Security and Fire Doors
• Frequently Asked Questions
• Related Guides

Which Lock or Latch Suits Your Door?

Tubular Latches: Internal Doors Without Locking

A tubular latch holds a door closed using a spring-loaded latch bolt. Turning the handle or knob rotates the spindle and retracts the latch.

This type of mechanism is commonly used on living-room, dining-room and bedroom doors where no locking function is required.

Standard and heavy-duty latches

A sprung lever handle may only require a standard latch because the handle contains its own return spring. An unsprung door knob or lever normally requires a sufficiently strong double-sprung or heavy-duty latch to return it after use.

Our 3-inch heavy-duty tubular latch is designed for use with unsprung knobs and handles. Check the individual product specification rather than assuming every latch can return heavy or unsprung furniture.

Backset and case length

The nominal 2.5-, 3- or 4-inch measurement normally describes the latch’s overall case length rather than its backset. The backset is the distance from the faceplate to the centre of the spindle follower.

A deeper backset is often useful with door knobs because it creates more hand clearance between the knob and the door frame.

Read Choosing the Right Tubular Latch for a complete measurement guide.

Bathroom Privacy Options

Bathroom hardware provides privacy rather than entrance-door security. A suitable arrangement should lock from inside while allowing emergency access from outside.

Bathroom sash lock

A bathroom sash lock combines a handle-operated latch and a privacy bolt within one case. The handle or knob operates the latch, while a separate turn-and-release set operates the privacy bolt.

The handles and turn must match the lock’s spindle sizes and operating centres. Our 3-inch bathroom sash lock is not double-sprung, so its compatibility with the selected handles or knobs should be checked carefully.

Separate tubular latch and bathroom deadbolt

With this arrangement, the handle or knob operates a tubular latch while a separate turn-and-release set operates the bathroom deadbolt.

Separating the two mechanisms gives more freedom over the position of the privacy control. This can be helpful with door knobs that need a deeper backset or additional clearance from the frame.

The bathroom deadbolt does not replace the everyday latch. Both mechanisms are required if the door must latch closed when it is not locked.

Sash Locks

A mortice sash lock combines a sprung latch and locking bolt in one case.

The handle or knob operates the latch so that the door can be opened and closed during normal use. A key, cylinder or privacy control operates the locking bolt separately.

Sash locks are available for different internal and external applications. Do not assume that every sash lock provides external-door security simply because it uses a key or contains several levers. Check its intended use and certification.

Mortice Deadlocks

A mortice deadlock contains a locking bolt but no handle-operated latch.

It may be used where a door requires a separate locking function. If the door must also remain closed while unlocked, it will require another latching mechanism or a sash lock that combines both functions.

A bathroom deadbolt and a security deadlock are not interchangeable. Bathroom products provide privacy, while entrance-door deadlocks must be specified and tested for their intended security application.

Euro-Profile Locks and Cylinders

A euro-profile lock case accepts a separate removable euro cylinder.

The lock case contains the latch and/or locking bolt. The cylinder provides the key or thumbturn operation. Because they are separate components, the correct case and cylinder must be selected together.

Before ordering, check:

• The lock case function and dimensions
• The handle-to-cylinder operating centres
• The cylinder profile and overall length
• The required internal and external cylinder projection
• Whether key/key or key/thumbturn operation is required
• The product’s stated security rating and intended application

Our 3-inch Euro sash lock, for example, is a lock case and does not include the handles or cylinder. Always check the supplied components rather than assuming everything pictured is included.

If the door already uses a multipoint mechanism, follow its specific measurements and requirements. A conventional sash lock is not a direct replacement. Read What Is a Multipoint Door Lock?

Night Latches

A night latch is normally mounted on the internal face of an entrance door and operated by a key cylinder from outside. Many models latch automatically when the door closes.

Automatic latching is convenient but can result in accidental lockouts. Some night latches also include hold-back or deadlocking features, although the available functions vary by model.

The term “night latch” does not confirm a particular security rating. Check the selected product’s certification, backset, cylinder and compatibility with the door. Browse our night latches.

Rim Locks

A rim lock is mounted on the face of a door rather than recessed into its edge. The visible case normally contains a sprung latch and either a key-operated bolt or privacy control.

Our rim locks are intended for internal doors and are particularly suited to cottages, period properties and traditional interiors.

Rim locks normally require dedicated rim lock knobs. Check the spindle, rose arrangement, keeper, case dimensions and whether the lock is handed or reversible.

Do not rely on a decorative internal rim lock as the principal security lock for an external entrance door. For bathroom versions, check whether external emergency access is provided.

Cabinet Latches

Cabinet latches hold cupboard and cabinet doors closed. Depending on the design, they may use a sprung bolt, magnetic catch, turn or mechanical latch.

Match the latch and keep to the cabinet construction and opening direction. A standard cabinet latch should not be assumed to provide key locking, child resistance or a substitute for room-door hardware.

Checks Before Ordering

• Required function: does the door need to latch, provide privacy or provide tested security?
• Case length and backset: check the technical drawing rather than relying only on the nominal inch size.
• Operating centres: handle-to-keyhole, cylinder or turn distances must match the selected furniture.
• Door dimensions: check the thickness, available timber, existing cut-outs and fixing positions.
• Spindle compatibility: confirm the spindle size and required length.
• Springing: make sure the latch or lock can return the selected knob or handle.
• Handing: determine whether the latch or lock is reversible or must be ordered in a particular orientation.
• Supplied components: check for the keep, faceplate, screws, spindle, handles, cylinder, keys, escutcheons and turn-and-release set as applicable.
• Finish and environment: confirm whether the hardware is intended for internal or external use.

Security and Fire Doors

Five levers, a particular pin count or a key-operated mechanism do not by themselves prove that a lock meets a recognised security standard. Check the exact product certification, intended application and any requirements specified by your insurer.

Fire performance is a separate consideration. Hardware fitted to a certified fire door must be suitable for the complete tested or certified door assembly and installed in accordance with its supporting documentation.

A latch, lock or hinge carrying fire-related certification does not automatically make an otherwise untested door assembly compliant. Seek suitable professional advice before altering a fire door, escape door or communal entrance.

Frequently Asked Questions

What is the difference between a lock and a latch?

A latch holds a door closed and releases when its handle or knob is operated. A lock adds controlled locking through a key, cylinder, bolt or privacy mechanism.

Is a tubular latch a mortice latch?

A tubular latch is morticed into the edge of the door. “Mortice” describes the recessed fitting method, so tubular and mortice are not necessarily opposing categories.

Which lock do I need for a bathroom door?

Common options are a bathroom sash lock or a separate tubular latch and bathroom deadbolt. Use compatible handles or knobs and a turn-and-release arrangement that permits emergency access from outside.

Can I add a bathroom turn to any door handle?

No. The turn requires a compatible bathroom lock or deadbolt. Check the spindle size, operating centres, fixing positions and available space before ordering.

Does a euro-profile lock include a cylinder?

Not necessarily. The lock case and cylinder are separate components and may be sold separately. Handles and protective furniture may also need to be ordered separately.

Does every external door need a five-lever lock?

No. The correct arrangement depends on the door system, security specification, escape requirements and insurer’s conditions. Lever count alone does not establish certification or suitability.

Does a tubular latch lock a door?

No. A standard tubular latch keeps the door closed but does not provide privacy or security locking.

Can an internal rim lock be used on a front door?

The rim locks in our current collection are intended for internal doors and should not be relied upon as the principal security lock for an external entrance door.

Related Guides

• Different Types of Latches
• How to Choose Handles for an Internal Door
• Choosing the Right Tubular Latch
• What Is a Sash Lock?
• Are Door Handles Universal?
• Rim Lock or Mortice Latch: Which Do You Need?