MagSafe-style magnet rings are widely used in magnetic phone cases, wireless chargers, power banks, car mounts, charging stands, wallets, and other consumer-electronics accessories.
MagSafe-style magnet rings are widely used in magnetic phone cases, wireless chargers, power banks, car mounts, charging stands, wallets, and other consumer-electronics accessories.
Although many magnet rings look similar, their dimensions and magnetic performance are not necessarily the same. Small differences in ring diameter, magnet thickness, segment position, adhesive, or polarity can affect:
This guide explains the main dimensions of a MagSafe magnet ring, which parameters can be customized, and what information buyers should provide when developing a custom magnetic assembly.
The main dimensions normally include:
There is no single commercially available magnet-ring size suitable for every MagSafe-style or Qi2-related product.
The final dimensions should be selected according to the product housing, charging-coil position, required holding force, working air gap, temperature, and compatibility target.
A MagSafe magnet ring is a circular magnetic assembly used to align and attach a phone or accessory.
It normally consists of:
The ring helps position the charging coils and provides mechanical attachment. It does not generate or transmit wireless charging power by itself.
In many products, a separate orientation magnet is added below the main ring. This helps control the rotational position of accessories such as wallets, stands, and power banks.
No.
Many standard rings sold in the market use similar general layouts, but dimensions can vary between manufacturers and applications.
Differences may include:
A ring that fits one phone case may not fit another wireless charger or power bank.
For OEM and ODM projects, buyers should not rely only on a supplier’s statement that a ring is “standard MagSafe size.” The drawing and actual dimensions should be confirmed before sampling.
Commercial MagSafe-style magnetic rings often fall within the following general reference ranges:
| Parameter | Common market reference |
|---|---|
| Ring outer diameter | Approximately 54–56 mm |
| Ring inner diameter | Approximately 44–46 mm |
| Radial magnetic width | Approximately 4–6 mm |
| Magnet thickness | Approximately 0.5–2.0 mm |
| Number of ring segments | Commonly 16–20 pieces |
| Total assembly thickness | Depends on magnet, carrier, adhesive, and cover |
| Orientation magnet | Customized according to product layout |
| Segment gap | Determined by polarity, assembly, and dimensional design |
These are general commercial reference ranges—not universal Apple, MagSafe, or Qi2 certification dimensions.
The correct dimensions must be confirmed using:
For products intended for Apple’s MagSafe ecosystem, developers should review the current Apple accessory requirements. For Qi2 products, applicable requirements should be confirmed through the Wireless Power Consortium and its authorized testing process.
The outer diameter determines the total space required by the magnetic ring.
It affects:
A larger outer diameter may increase the available magnetic area, but it also requires more internal space.
The outer diameter must not interfere with:
The inner diameter defines the open area inside the magnetic ring.
This space may contain:
If the inner diameter is too small, the magnet ring may interfere with the charging coil or other components.
If it is too large, the magnetic ring may have less magnetic area or may not align correctly with the mating product.
The inner diameter should therefore be selected together with the coil and shielding design.
Radial width is the distance between the outer and inner edges of the ring.
It can be calculated approximately as:
Radial width affects:
Increasing the width may increase magnetic material volume, but magnetic performance still depends on thickness, grade, pole arrangement, and the mating structure.
Magnet thickness is one of the most important design parameters.
A thicker magnet may provide:
However, increasing thickness may also cause:
The thinnest possible magnet is not always the best choice either. A magnet that is too thin may not provide enough force after adding the housing, adhesive, coating, and phone case.
The correct thickness should be determined through magnetic analysis and prototype testing.
Magnet thickness and total assembly thickness are not the same.
Total assembly thickness may include:
For example, a 1.0 mm magnet does not necessarily create a 1.0 mm finished magnetic assembly.
Buyers should specify both:
This helps prevent problems when closing the housing or fitting the component into a limited internal space.
A magnet ring is normally made from multiple individual magnet segments.
The segment quantity affects:
More segments can provide greater design flexibility, but they also increase assembly and polarity-control requirements.
The ideal quantity depends on:
The buyer and supplier should approve a polarity drawing before sample production.
Each magnet segment should be defined by:
The spacing between segments also matters.
Uneven spacing may cause:
For mass production, the supplier should control each segment position through a carrier, fixture, or automated assembly process.
Many magnetic assemblies include an additional magnet below the main ring.
This orientation magnet may help:
Important parameters include:
The orientation magnet should not be designed independently from the ring. Its location and polarity must be evaluated as part of the complete magnetic system.
The carrier holds the individual magnet segments in position.
Common carrier materials include:
The carrier affects:
A weak or inaccurate carrier may deform during transportation or assembly, causing the magnet segments to move.
Important carrier requirements include:
Many magnetic rings are supplied with pre-applied adhesive.
The adhesive layer affects both total thickness and working air gap. Even a small increase in adhesive thickness may reduce the final magnetic force.
The adhesive should be selected according to:
Common housing materials include:
Testing should be performed on the actual product surface whenever possible.
The magnetic ring must be positioned correctly relative to the wireless charging coil.
Important positioning requirements include:
Poor concentricity may contribute to:
A professional drawing should define the center datum and positional tolerances.
A magnetic ring should remain flat after assembly.
Poor flatness may create:
Flatness can be affected by:
The supplier should inspect the complete ring rather than only checking individual magnet dimensions.
A professional magnetic assembly supplier can normally customize:
| Customization item | Possible adjustment |
|---|---|
| Outer diameter | Match available product space |
| Inner diameter | Fit the charging coil and shielding |
| Magnet thickness | Balance force and product thickness |
| Segment quantity | Adjust magnetic layout and manufacturing method |
| Segment shape | Arc, block, trapezoid, or custom geometry |
| Pole arrangement | Match the intended mating product |
| Orientation magnet | Adjust size, position, and polarity |
| Carrier | PET, plastic, molded, or custom structure |
| Adhesive | Selected for the actual housing material |
| Coating | Nickel, zinc, epoxy, or custom protection |
| Magnet grade | Selected for strength and temperature |
| Holding force | Adjusted for the target user experience |
| Complete assembly | Integrated with carrier, adhesive, or housing |
Customization should begin with the complete product requirement—not simply a desired magnet-ring diameter.
The magnetic holding force is influenced by several dimensional factors.
A wider ring or larger segment area may increase magnetic interaction, but the benefit depends on the mating structure and magnetic circuit.
Increasing thickness may increase magnetic output, especially when the original magnet is very thin. However, the improvement becomes smaller when the magnetic circuit approaches saturation.
Reducing the distance between the magnetic components is often one of the most effective ways to improve actual holding force.
Correct segment position, polarity, concentricity, and flatness can improve force consistency without changing the magnet grade.
For this reason, product designers should not rely only on upgrading from N48 to N52. Dimensional and structural optimization may provide better results.
The magnet ring does not transfer charging power, but its dimensions and position can influence the complete charging system.
An unsuitable ring design may contribute to:
Wireless charging performance also depends on:
The complete product must therefore be tested as one integrated system.
Use the following general design logic:
The final thickness should be confirmed through sample testing. Increasing magnet thickness without considering the complete magnetic circuit may increase cost without producing the expected improvement.
Common neodymium magnet grades may include:
A higher numerical grade normally indicates a higher maximum energy product, but it does not mean that it is always the best material.
Grade selection should consider:
For wireless charging products exposed to higher temperatures, resistance to irreversible demagnetization may be more important than maximum room-temperature magnetic strength.
Sintered NdFeB magnets can corrode without suitable surface protection.
Common coatings include:
The selected coating may slightly affect magnet dimensions and assembly tolerance.
Coating selection should consider:
For demanding environments, coating alone may not be sufficient. Plastic overmolding, sealing, or encapsulation may be required.
A custom magnet-ring drawing should include:
The supplier should confirm which dimensions are measured during incoming inspection, in-process inspection, and final inspection.
A typical customization project may follow these steps:
The buyer provides the product application, drawing, available space, mating structure, and performance target.
The supplier reviews:
Both parties approve:
The supplier produces engineering samples for assembly and performance testing.
The buyer tests:
The magnet thickness, grade, ring size, carrier, adhesive, or pole arrangement can be adjusted according to the test results.
Both parties confirm the approved sample, drawing, inspection method, acceptance criteria, packaging, and batch-traceability requirements.
The following format can be used when requesting a custom magnetic ring:
Application: Magnetic wireless charging power bank
Ring outer diameter: ___ mm
Ring inner diameter: ___ mm
Magnet thickness: ___ mm
Maximum assembly thickness: ___ mm
Segment quantity: ___ pieces
Orientation magnet: Required / Not required
Pole arrangement: According to approved polarity drawing
Working air gap: ___ mm
Target holding force: ___ to ___ N
Operating temperature: ___°C
Carrier material: ___
Adhesive requirement: ___
Coating: ___
Sample quantity: ___ pieces
Annual demand: ___ pieces
Required tests: Dimensions, polarity, pull force, temperature, and adhesive
Required documents: Dimensional report, polarity drawing, material data, and inspection report
If some dimensions are unknown, provide the complete product structure and performance target. The supplier can then recommend a practical starting design.
Avoid the following mistakes:
A complete specification reduces redesign, assembly problems, and mass-production risk.
MagSafe is an Apple trademark and technology ecosystem. Product developers targeting Apple-device compatibility should follow Apple’s current accessory-design and authorization requirements where applicable.
Qi2 is a wireless charging standard developed by the Wireless Power Consortium. Its Magnetic Power Profile uses magnetic attachment and alignment to position charging devices.
A loose magnet ring or magnetic assembly is not automatically:
Certification and authorization generally concern the complete product and its compliance with the applicable requirements.
The Wireless Power Consortium confirms that Qi2 uses magnetic alignment, while Apple publishes accessory design guidance for developers. Final dimensions and certification requirements should be checked against the latest applicable documents rather than copied from a generic commercial ring. Apple Accessory Design Guidelines, Wireless Power Consortium.
There is no single commercial dimension that should be assumed for every project. Many market products use an outer diameter of approximately 54–56 mm, but the correct dimension depends on the intended device, coil position, housing, magnetic layout, and applicable ecosystem requirements.
Commercial magnet rings often use an inner diameter of approximately 44–46 mm. This is only a market reference range. The final inner diameter must fit the charging coil, shielding, and product structure.
Individual magnet thickness commonly falls within approximately 0.5–2.0 mm, depending on the application. The complete assembly will be thicker after adding the carrier, adhesive, back plate, or protective structure.
Many commercial rings contain approximately 16–20 magnet segments, but the quantity can vary. Segment quantity, position, and polarity should be defined in an approved engineering drawing.
Yes. The outer diameter, inner diameter, width, thickness, segment quantity, carrier, adhesive, and orientation magnet can be customized according to the available product space and performance target.
Yes. Magnet thickness, magnetic area, working gap, segment position, and magnetic-circuit design can all affect holding force. However, stronger is not always better because the product must still be comfortable to remove.
Not always in direct proportion. The result depends on the magnetic circuit, mating structure, working gap, and material saturation. Sample testing is required.
Not directly. The ring helps align the charging coils, but charging speed also depends on the coils, electronics, power source, thermal design, shielding, communication, and complete certified system.
The supplier should provide a dimensional drawing and polarity drawing showing the ring size, magnet thickness, segment positions, orientation magnet, carrier, adhesive, tolerances, and magnetization direction.
Provide the application, product drawing, available space, mating structure, working air gap, target holding force, temperature, sample demand, and annual volume.
MagSafe magnet ring dimensions should not be selected by copying only an outer diameter from a standard market product.
A complete specification should define:
The correct magnetic ring must fit the product structure, align the charging coils, provide stable attachment, allow comfortable removal, and maintain consistent performance during mass production.
Prototype testing inside the actual product is the most reliable way to confirm the final dimensions.
AIM Magnet develops and manufactures custom neodymium magnets and magnetic assemblies for wireless charging, consumer electronics, motors, sensors, and other precision applications.
We can support:
Send us your product drawing, available space, mating structure, working air gap, target holding force, operating temperature, and estimated order volume for an engineering evaluation.
