How to Choose the Right Door Knob

Author: Carl Benson

Carl is the founder of Suffolk Latch Company, with a background in engineering and over 20 years’ experience in home hardware. He works closely with suppliers and designers alike to develop quality ironmongery that stands the test of time. Read my full bio.

How to Choose Door Knobs

Choosing door knobs is easier when you start with the door, not the finish. The right door knob depends on how the door works, what lock or latch it uses, how much hand clearance there is, and whether the room needs privacy, security or simply a way to pull the door closed.

This guide explains the practical checks to make before ordering. If you are still at the early research stage, you may also find our main guide useful: Door Knobs Explained: The Complete Guide.

To browse the full range, visit our Door Knobs Collection.

Table of Contents

Start with the Door

The best way to choose a door knob is to work backwards from the door itself. A door knob is only one part of the door hardware. It needs to work with the latch, lock, spindle, rose plate, door thickness and frame position.

A common mistake is to choose the style first and only later discover that the door needs a different latch, a longer backset or a dedicated rim lock knob set. This can lead to extra filling, re-cutting, returns or a door knob that does not feel right in daily use.

Before choosing the final finish, ask these questions:

• Is the door internal or external?
• Does the door need to latch, lock or simply pull open?
• Is the lock or latch fitted into the edge of the door or mounted on the surface?
• Is the door thick enough for the chosen latch or lock?
• Does the door knob need to be sprung or unsprung?
• Is there enough space between the knob and the door frame?

Once those points are clear, choosing the style becomes much simpler.

Beehive Door Knobs Ebonised

Beehive Door Knobs Rosewood

Internal, Bathroom, Cupboard or External?

For standard internal doors, such as living rooms, dining rooms and hallways, a door knob is normally used with a simple tubular latch or mortice latch. The latch keeps the door closed and the knob turns the spindle to retract it.

Bathrooms and WCs need more thought. A bathroom door should normally use a privacy lock with a turn and release. This allows the door to be secured from inside, while still allowing emergency access from outside using a coin or flat screwdriver. This is much safer than a simple surface bolt, particularly in homes with young children, older relatives or anyone who may need assistance.

Cupboard doors do not always need a working latch. If the door knob is being used as a pull, you may need a fixed rose, dummy fitting or a roller catch to hold the door closed. In this situation, the knob is not operating a latch in the usual way.

External doors need the most care. The door knob itself is not the main security device. The security should come from a suitable lock that meets the requirements of the door and, where relevant, your home insurance policy. Material choice also matters outside. Brass, bronze and stainless steel are generally better suited to exposed external use than wood or cast iron.

Is the Lock Rim or Mortice?

Before ordering door knobs, check whether the door uses a rim lock or a mortice latch or lock.

A mortice latch or lock is fitted into a recess cut into the edge of the door. This is the most common arrangement on modern internal doors. With this type of fitting, the door knobs normally fix to the timber face of the door on both sides.

A rim lock is different. It is surface-mounted on the face of the door and remains visible. Rim locks are common in period properties, cottages and older internal doors. They need a dedicated rim lock door knob set because the knob on the lock side usually sits directly against the lock case, while the opposite knob fixes to the timber door with a rose plate.

If you are unsure which type you have, look at the inside face of the door. If you can see a metal lock case fixed to the surface, it is almost certainly a rim lock. If the mechanism is hidden inside the edge of the door, it is likely to be a mortice latch or mortice lock.

For more detail, read Rim Lock vs Mortice Door Knobs and Rim Lock Door Knobs Explained.

Pewter Octagonal Cast Iron Door Knobs

Black Octagonal Cast Iron Door Knobs

Does the Door Need to Latch, Lock or Pull?

Not every door needs the same hardware. A passage door, such as a hallway or living room door, usually only needs a latch. A bedroom or study may need a key lock. A bathroom needs privacy rather than security. A cupboard may only need a pull knob and a catch.

For a simple internal door, a tubular latch is usually sufficient. For an internal door that needs to lock with a key, a 3-lever mortice sash lock may be suitable. For bathrooms, a bathroom mortice lock with a separate turn and release is normally the better choice.

For external doors, the requirements are different. A traditional door knob may operate a latch, but the security should come from a proper external lock, such as a suitable British Standard lock or another approved locking system. Always check your insurer’s requirements before relying on a lock for an entrance door.

For a fuller explanation of locking arrangements, read Door Knobs With Locks Explained.

Sprung or Unsprung Door Knobs

Door knobs can be sprung, sprung on one side or unsprung.

A sprung door knob has a spring built into the knob or rose. This helps return the knob after it has been turned. Sprung knobs can be useful when replacing older lever handles or when working with a latch that has become slightly soft with age.

An unsprung door knob has no built-in return spring. It relies entirely on the spring inside the latch or lock. Many traditional wooden, brass and cast iron door knobs are unsprung, so they should normally be used with a good quality heavy-duty latch or lock.

If an unsprung knob is fitted to a weak latch, the knob may not return properly. If too much spring tension is used, the knob can feel stiff, which may not suit young children or users with reduced grip strength. The aim is to choose a combination that returns cleanly without feeling unnecessarily hard to turn.

What Backset Do You Need?

The backset is the distance from the edge of the door to the centre of the spindle hole. It is one of the most important measurements when fitting door knobs.

Door knobs usually need a deeper backset than lever handles. A lever handle moves your hand away from the door frame, but a knob has to be gripped around its outer edge. If the backset is too short, your knuckles may catch the door stop or frame every time the door is opened.

As a general guide, 64mm or 2½ inches should usually be treated as the minimum for many door knob installations. Where the door design allows it, a 76mm to 102mm backset, or 3 to 4 inches, often gives better clearance and a more balanced appearance.

Traditional panelled doors often have a wider central rail, which can allow the knob to sit further into the door without looking out of place. Modern or narrow-stile doors may give you less flexibility, so measuring before ordering is important.

Check Hand Clearance from the Frame

Hand clearance is closely linked to backset. Even if the latch technically fits, the finished door may still feel awkward if the knob is too close to the frame.

This is especially important when replacing lever handles with door knobs. Existing lever handles are often fitted close to the door edge because they do not require as much hand clearance. A door knob fitted in the same position may be uncomfortable to use.

Before ordering, check the diameter of the door knob, the thickness of the door stop and the position of the existing latch. If there is not enough clearance, it may be better to fit a new latch with a longer backset and make good the old fixing marks.

Plain White Ceramic Door Knob on Rose

Skipton Cream Crackle Door Knob on Rose

Is the Door Thick Enough?

Most modern internal doors in the UK are around 35mm thick, while many internal fire doors are around 44mm thick. These will usually accept modern mortice latches and locks.

Older period doors can be thinner. Some were originally designed for surface-mounted rim locks rather than mortice latches. Cutting a modern mortice into a thin old door can remove too much timber and weaken the structure.

This is one reason rim locks remain useful in period properties. Because the lock sits on the surface of the door, far less timber needs to be removed. If you are working with original doors, measure the thickness carefully before deciding whether to fit a new mortice latch or retain a rim lock arrangement.

Will the Rose Cover Old Marks?

If you are replacing existing door furniture, check the size of the rose plate before ordering. Removing old handles or knobs can reveal screw holes, paint shadows or witness marks on the door.

A larger rose may cover some marks, but this should not be assumed. Product drawings are useful here because they show the rose diameter, knob projection and fixing positions. If the new rose is smaller than the old one, you may need to fill, sand and redecorate the affected area.

This is particularly important when replacing lever handles with door knobs, as lever plates often leave larger marks than a round rose will cover.

Hammered Reeded Antique Door Knob

Hammered Reeded Polished Bronze Door Knob

Choosing the Material and Finish

Once the mechanism, backset and door type are clear, you can choose the material and finish.

Wooden door knobs suit many traditional interiors and period properties. Rosewood and ebonised finishes are common choices, particularly with antique brass roses and traditional rim locks. For more detail, read Wooden Door Knobs Explained.

Beehive door knobs are a popular traditional style, especially in Georgian and Victorian homes. They are available in wood and brass, with different versions for rim locks and mortice latches. Read What Are Beehive Door Knobs? for a fuller explanation.

Cast iron door knobs have a heavier feel and suit cottages, utility rooms and traditional interiors. They are best used with the right latch and in suitable indoor conditions. Read Cast Iron Door Knobs Explained.

Antique brass door knobs are useful when you want an aged brass appearance from the start. They can work particularly well in period homes, but it is important to understand how the finish behaves and how it differs from aged brass. Read Antique Brass Door Knobs Explained.

Related Reading

These supporting guides explain the main choices in more detail:

• Door Knobs Explained: The Complete Guide
• Rim Lock Door Knobs Explained
• Rim Lock vs Mortice Door Knobs
• Door Knobs With Locks Explained
• What Are Beehive Door Knobs?
• Wooden Door Knobs Explained
• Cast Iron Door Knobs Explained
• Antique Brass Door Knobs Explained
• Choosing Door Knobs for a Victorian House

Conclusion

The safest way to choose door knobs is to start with the practical details. Check the door type, lock or latch, backset, hand clearance and door thickness before choosing the style or finish.

Once the mechanism is right, you can choose a door knob that suits the property and the way the room is used. For the full range, browse our Door Knobs Collection.

FAQ

How do I know which door knob I need?

Start by checking the door type and the lock or latch already fitted. A standard internal door usually uses a mortice latch or tubular latch, while a door with a surface-mounted rim lock needs a dedicated rim lock door knob set. Bathrooms need privacy hardware, and external doors need a suitable security lock.

What size door knob should I choose?

The size should suit both the door and the available hand clearance. Larger knobs can be comfortable to use, but they need enough backset so your knuckles do not hit the frame. Always check the knob diameter and the latch backset before ordering.

Can I replace door handles with door knobs?

Yes, but check the existing latch position first. Lever handles are often fitted closer to the edge of the door than is ideal for knobs. You may need a latch with a longer backset and some making good where the old handle was removed.

Why does my door knob not turn properly?

The most common causes are a weak latch spring, poor alignment, or using an unsprung door knob with a latch that is not strong enough. The spindle, latch and knob roses must also line up correctly on both sides of the door.

What latch do I need for an unsprung door knob?

An unsprung door knob should normally be used with a heavy-duty latch or a good quality lock with a strong return spring. The latch needs enough spring strength to return the knob after it has been turned.

Are door knobs suitable for people with reduced grip?

They can be, but care is needed. Larger, textured or shaped knobs may be easier to use, but lever handles are often a better option where grip strength or accessibility is a concern.