A cupboard door that will not stay shut, a display panel that slips or a tool holder that drops its load usually has the same root cause: the magnet was chosen by size rather than performance. Magnet pull ratings give you a practical way to compare strength before you buy, but only when you understand what the number is actually measuring.

For DIY, trade and fabrication work, a pull rating is a useful starting point, not a guarantee that a magnet will hold that exact weight in every position. Surface condition, fixing method, the gap between materials and the direction of force all affect the result. Selecting the right magnet means matching its real working conditions to the job.

What are magnet pull ratings?

A magnet pull rating is the force required to pull a magnet directly away from a suitable steel surface. It is commonly shown in kilograms or kilograms-force as a simple indication of holding power. A magnet rated at 10kg pull is tested to resist a straight, controlled pull of around that level under ideal conditions.

That wording matters. The test normally uses a flat, clean, thick piece of mild steel with full contact between the magnet and the surface. There is no paint, no air gap, no sideways loading and no sudden impact. It is a controlled comparison figure that helps you judge one magnet against another.

A higher pull rating generally means a stronger hold, especially when comparing magnets of a similar type and shape. It does not mean the magnet can safely support that same weight from a vertical surface, hold a moving object or secure a fitting that is regularly pulled, knocked or twisted.

Why real-world holding strength can be lower

Neodymium magnets are exceptionally powerful for their size, particularly N52 magnets, but magnetic force changes quickly when the conditions are less than ideal. A small detail in the build can make a large difference to usable holding strength.

A gap reduces pull fast

Magnets work best with direct metal-to-metal contact. Paint, powder coating, laminate, fabric, adhesive pads, rust and even a thin uneven surface introduce a gap. The larger that gap becomes, the more the holding force drops.

This is particularly relevant for cabinet catches and concealed closures. If a magnetic catch is mounted behind a thick door face or if the strike plate sits proud of the surface, a magnet with an impressive quoted pull rating may feel weaker than expected. Keep the contact faces as close and as square as the installation allows.

Steel quality and thickness matter

Magnet pull ratings are usually established on thick mild steel. A thin steel plate may not carry the magnetic field as effectively, so the holding force can be lower. Stainless steel can also be a poor choice, as many grades are only weakly magnetic or not magnetic at all.

Where possible, use a plain steel strike plate with enough thickness to provide a dependable target. If you are fitting a catch to a lightweight steel panel, test it first rather than assuming the panel will perform like a solid steel plate.

Pull direction changes the result

The published rating refers to direct pull – straight away from the steel face. A magnet used to hold something on a wall, underside of a shelf or vertical panel is often dealing with shear force instead. In that position, the object is trying to slide down rather than pull directly away.

Friction between the magnet and steel helps resist sliding, but it is not the same as the stated pull force. Vibration, a smooth painted surface or a sudden knock can reduce grip further. For wall-mounted tools, retail displays and removable panels, allow a generous safety margin and consider a mechanical stop, lip or support rail to carry the weight.

Leverage and movement create extra force

A long handle, wide door or projecting panel can put leverage on a magnet. The further the load is from the fixing point, the easier it becomes to peel the magnet away from its steel target. Repeated opening, closing and vibration also create short bursts of force that a static pull test does not replicate.

For these jobs, one very strong magnet is not always the best answer. Two or more magnets placed to resist twisting can provide a more stable closure or mount.

Choosing magnet pull ratings for your application

Start with the task, then choose the format and rating that suit it. A compact disc magnet may be ideal for a hidden closure, while a block magnet offers a larger contact area for jigs, holders and mounting work. Countersunk magnets are designed for secure screw fixing where a flush, tidy installation is needed.

For a light cabinet door, the goal is usually reliable closure rather than maximum force. Too much pull can make a door awkward to open, especially on small furniture or where children and older users will use it. A magnetic catch with a suitable strike plate gives predictable alignment and a practical opening feel.

For a removable access panel, consider the panel weight, how often it will be removed and whether it can be lifted away cleanly. If it must be pulled from one edge, account for the peeling action. Several magnets around the perimeter can reduce flexing and keep gaps even.

For workshop fixtures, tool storage and fabrication, focus on direct contact and load direction. A magnet holding a steel tool vertically is working in a less favourable way than one clamping two flat surfaces together. Build in a physical support where safety or repeated use is involved.

Use a realistic safety margin

There is no single multiplier for every project because the material, finish and movement vary. As a sensible rule, do not select a magnet based on a pull rating that only just matches the item being held. Leave meaningful spare capacity, particularly where there is a coated surface, a vertical load, vibration or a risk of accidental impact.

If failure would damage the item or create a hazard, use magnets as part of the fixing system rather than the only support. A locating pin, bracket, retaining lip or conventional fastener can turn a strong magnetic hold into a dependable installation.

Magnet size, grade and shape all play a part

A larger magnet is not simply stronger because it contains more material. Its shape and contact face affect how it performs. A wider disc may offer more contact area against a steel plate, while a thicker magnet can provide greater field strength through a small gap. A block magnet may suit a straight edge or wider mounting surface better than a round disc.

N52 neodymium magnets are a high-grade option chosen where compact dimensions and superior pull performance matter. They can deliver substantial force from a small component, making them useful for discreet catches, space-limited installations and stronger custom builds. That strength also means they need careful handling.

Countersunk magnets deserve separate consideration. The hole and countersink reduce the amount of magnetic material, so compare their ratings with other countersunk options rather than assuming they will match a solid disc of the same diameter. Their advantage is secure, accurate screw mounting without a bulky bracket.

How to test a magnet before final fitting

A quick trial fit is worthwhile when the application is demanding. Fit the magnet and steel target in their intended positions, including any paint, timber, panel material or adhesive that will be present in the finished job. Test the opening action, alignment and resistance to knocks.

For a closure, check that the door or panel meets the magnet squarely. For a vertical hold, add the expected load and gently introduce movement. If it slides, twists or releases too easily, improve the contact surface, add a second magnet or choose a higher-rated option. Testing the actual assembly is far more useful than judging strength by hand.

Handle high-strength magnets with care

Powerful neodymium magnets can snap together unexpectedly. Keep fingers clear when bringing magnets near steel or another magnet, and handle larger pieces one at a time. They can chip or crack if allowed to collide, even though their pull strength is high.

Keep strong magnets away from pacemakers and other medical devices, and store them out of reach of children. They should also be kept clear of cards, storage media and sensitive electronics. When fitting countersunk magnets, tighten screws carefully: overtightening can damage the brittle magnet body.

The best result comes from treating a pull rating as a clear performance comparison, then designing for the surface, load and movement your project will actually face. Choose enough strength for a confident hold, leave room for real-world variables and your magnetic fixing will feel powerful for the right reasons.