Choosing the right maglock is not just about picking the biggest number on the box. If the lock is too weak, it may not suit the door or the site. If it is too strong, you could end up overspending on a setup that is more than the job needs. That is why so many installers, electricians, and buyers ask the same question: what size maglock do I need?
This guide explains how to choose the right size of magnetic door locks for different doors and applications. We will cover common holding forces, the difference between single and double maglocks, when to use surface-mounted or mortice options, and why brackets, armature plates, and safety devices matter just as much as the lock itself.
If you are buying maglocks UK professionals can rely on, this article will help you make a more informed choice.
What Is a Maglock?
A maglock, or magnetic lock, is a type of locking device that uses an electromagnet and an armature plate to secure a door. When power is applied, the magnet holds the plate firmly in place and keeps the door locked. When power is removed, the door releases.
These electromagnetic door locks are widely used in access control because they are simple, reliable, and well suited to high-traffic doors. They are often found on commercial entrances, communal doors, internal secure areas, and controlled exits.
Many access control maglocks are used alongside keypads, fob readers, video entry systems, exit buttons, and emergency break glass units.
How Magnetic Door Locks Work
A maglock has two main parts:
- the magnet body fixed to the frame
- the armature plate fixed to the door
When the system is powered, the magnet creates a strong holding force that keeps the door shut. Unlike a latch or bolt, a maglock works through direct magnetic attraction.
This makes magnetic door locks a popular choice for:
- access-controlled office doors
- apartment block communal entrances
- schools and colleges
- healthcare sites
- internal secure rooms
- some external gates and doors
Because they rely on power to stay locked, maglocks are usually classed as fail safe. That means the lock releases when power is lost. This can be useful on doors where safe escape is important, but it also means the full system must be planned properly.
Why Maglock Size Matters
When people ask what size maglock do I need, they are really asking about holding force. Holding force is the amount of force needed to pull the door open when the maglock is engaged.
This is normally shown in pounds, such as:
- 300lb
- 600lb
- 1200lb
A higher number means a stronger holding force. The right choice depends on the size of the door, the material, whether it is internal or external, and how much pressure the door may face in day-to-day use.
Common Maglock Holding Forces
300lb Maglocks
A 300lb maglock is usually suited to lighter-duty applications. It can work well on smaller internal doors where traffic is low and the security requirement is modest.
Typical uses include:
- internal office doors
- store cupboards
- private staff areas
- lightweight timber doors
A 300lb unit is often a sensible choice where the door is not exposed to wind pressure or heavy public use. It is not usually the right option for demanding external doors or busy communal entrances.
600lb Maglocks
A 600lb maglock is a common middle-ground option. It offers stronger holding force than a 300lb unit and is often used on medium-duty doors.
Typical uses include:
- standard commercial doors
- shared internal entrances
- staff doors
- some timber and aluminium doors
For many sites, 600lb access control maglocks offer a good balance between strength, cost, and practical installation. They are popular where a 300lb lock feels too light, but a 1200lb unit would be more than necessary.
1200lb Maglocks
A 1200lb maglock is one of the most common choices for higher-security and higher-traffic applications. It is widely used on full-size commercial doors and busy entrance points.
Typical uses include:
- main commercial entrances
- apartment block communal doors
- schools
- warehouses
- external doors with proper protection
- metal or heavy timber doors
If you are dealing with a busy entrance, a large door leaf, or a site with higher security demands, 1200lb electromagnetic door locks are often the safer choice.
Choosing a Maglock by Door Type
The door itself plays a big part in the answer to what size maglock do I need. The same lock will not suit every material or application.
Internal Doors
Internal doors usually face less pressure than external doors. They are not exposed to wind, and many are lighter in weight.
For internal use:
- 300lb may suit lighter doors and lower-risk areas
- 600lb is often a strong general-purpose choice
- 1200lb may be used for larger or more secure internal doors
The best size depends on traffic levels and the value of the area being secured.
External Doors
External doors need more careful planning. They may face wind load, heavier frames, more forceful use, and higher security needs.
For many external applications:
- 600lb may suit some protected doors
- 1200lb is often preferred
- weather protection is essential
For outdoor projects, it is worth exploring External Maglocks designed for harsher conditions.
Timber Doors
Timber doors are common in offices, communal buildings, and residential blocks. They can work well with many maglock sizes, depending on the door thickness and use.
As a guide:
- lighter internal timber doors may suit 300lb or 600lb
- heavier or more important timber doors often suit 600lb or 1200lb
The frame strength and fixing method matter here just as much as the lock rating.
Aluminium Doors
Aluminium doors are common in commercial entrances. They are often used with access control because they suit electric locking well, but they can require specific brackets or mounting methods.
In many cases:
- 600lb or 1200lb is more common
- bracket choice is critical
- neat fitting matters for long-term performance
Glass Doors
Glass doors need specialist attention. You cannot treat them like a timber door and use standard fixings. In many cases, the lock setup will need a U bracket or other glass-specific hardware.
For glass doors:
- the lock size depends on the door size and use
- bracket compatibility is essential
- armature fitting must be correct
This is where Maglock Brackets become especially important.
Gates
Gates can be difficult because they are exposed to weather, movement, vibration, and misalignment. Not every maglock is suitable for gate use.
For gates:
- external-grade hardware is usually needed
- higher holding force is often preferred
- correct housing and protection matter
Gate applications should always be checked carefully before choosing standard maglocks UK stock.
Single Maglock vs Double Maglock
A single maglock secures one leaf of a door set. A double maglock is designed for double doors, with one magnet for each leaf.
When to Use a Single Maglock
Single units are common on:
- single entrance doors
- office doors
- store rooms
- communal single-leaf doors
When to Use a Double Maglock
Double units are used on:
- double commercial doors
- wide lobby entrances
- paired door sets in schools or public buildings
If only one leaf needs to open regularly, the setup may differ. Always check how the doors are used before choosing between single and double configurations.
Surface-Mounted vs Mortice Maglocks
Surface-Mounted Maglocks
Surface-mounted maglocks are the most common type. They are fixed to the face of the frame and door with suitable brackets and fixings.
Benefits include:
- easier installation
- broad compatibility
- common use in access control systems
- good choice for retrofits
Most access control maglocks used in everyday installations are surface-mounted.
Mortice Maglocks
Mortice maglocks are recessed into the door or frame for a more concealed finish. They are often chosen where appearance matters or where surface hardware would be less suitable.
Benefits include:
- cleaner appearance
- more discreet installation
- useful on certain high-end projects
However, they can be more complex to fit and may require more door preparation. They are not always the best choice for straightforward installations.
Weatherproof Maglocks for External Use
Not all magnetic door locks are built for exposed locations. If the door is outdoors or partly exposed, the lock must be able to handle moisture, temperature changes, and dirt.
Weatherproof or external-rated maglocks are often needed for:
- gates
- external communal doors
- service entrances
- perimeter access points
If the site is external, start with External Maglocks rather than standard indoor units.
Why Brackets and Armature Plates Matter
A maglock is only as good as its mounting. You can choose the right holding force, but if the bracket is wrong or the armature plate is not fitted properly, the lock will not perform as it should.
Maglock Brackets
Brackets help position the magnet and plate correctly on the door and frame. They are often essential where the door design does not allow a straight standard fit.
Common bracket types include:
- Z and L brackets
- U brackets for glass doors
- specialist housings for certain frame types
Without the right bracket, alignment problems are much more likely. That can reduce holding performance and cause unreliable operation.
You can browse suitable Maglock Brackets for different door types and installation needs.
Armature Plates
The armature plate is the part the magnet holds against. It must be fitted securely and aligned properly with the magnet face.
Poor armature installation can lead to:
- reduced holding force
- uneven contact
- noisy operation
- early wear
- unreliable locking
If you are asking what size maglock do I need, also ask whether the bracket and armature arrangement is correct for the door.
Fire Safety and Emergency Release Considerations
Fire safety should never be treated as an afterthought with electromagnetic door locks. Because maglocks rely on power to remain locked, they need safe release arrangements.
Why Maglocks Are Often Fail Safe
Most maglocks release when power is removed. This means they are usually fail safe. On many escape routes, this is helpful because the door can unlock during a power failure or fire alarm event.
Emergency Release Devices
A maglock system may need:
- an emergency break glass unit
- a press to exit button
- fire alarm interface
- correct power supply arrangement
These components help make sure people can exit safely in an emergency.
Fire Exit Planning
If the maglock is on a fire exit or escape route, the full setup must be planned carefully. Local regulations, the building fire strategy, and the specific use of the door all matter.
Installers and buyers should always make sure the lock, controls, and release devices are suitable for the door’s purpose.
Product Categories to Explore
If you are comparing maglocks UK options for a new project or replacement job, these Door Entry Online categories are the best place to start:
These categories cover standard internal units, external options, and the mounting hardware needed for a professional installation.
Common Mistakes When Choosing a Maglock
Choosing by Force Alone
A higher holding force is not always better. The lock must match the door, frame, and application.
Ignoring the Door Material
Glass, aluminium, timber, and steel doors all have different fitting needs.
Forgetting the Brackets
Many poor installations come down to incorrect or missing bracket selection.
Using Indoor Locks Outside
External doors need suitable weather-rated hardware.
Overlooking Fire Safety
A maglock must be part of a safe system, especially on escape routes.
FAQs
What size maglock do I need for an internal door?
It depends on the door size, traffic, and security needs. A 300lb lock may suit lighter internal doors, while 600lb is often a stronger all-round option.
Is a 1200lb maglock too much for a normal door?
Not always. A 1200lb maglock is common on commercial entrances and communal doors. It may be more than needed for a small private internal door, but it is often right for busier or more demanding sites.
Are magnetic door locks suitable for glass doors?
Yes, but they usually need specialist brackets and proper armature mounting. Glass door installations should always use compatible hardware.
Can I use a standard maglock on an external door?
Only if it is suitable for that environment. Many outdoor doors need weatherproof units. For those applications, look at External Maglocks.
What is the difference between surface and mortice maglocks?
Surface-mounted maglocks are visible and easier to install. Mortice maglocks are recessed for a neater finish but are often more complex to fit.
Why do maglock brackets matter?
Brackets help align the magnet and armature plate correctly. Without the right bracket, even a strong lock may not perform properly.
Are maglocks fail safe or fail secure?
Most maglocks are fail safe. That means they release when power is removed.
Can maglocks be used on fire exits?
They can be, but only when the full system is designed correctly with suitable emergency release and fire alarm interface arrangements.
Final Thoughts
If you are asking what size maglock do I need, the answer comes down to more than one number. You need to look at the door type, whether it is internal or external, the traffic level, the security requirement, and the supporting hardware around the lock.
For lighter internal doors, 300lb may be enough. For many standard commercial applications, 600lb is a practical choice. For busy entrances, communal doors, and heavier-duty applications, 1200lb is often the better fit.
Just as important, make sure the installation includes the right brackets, armature plates, power supply, and emergency release devices. That is what turns a maglock from a product into a reliable access control solution.
