# How to calculate the suction of powerful magnet?

As for the magnetic attraction, many people often ask, what is the attraction of a certain specification NdFeB magnet (powerful magnet)? Can the suction of the magnet be calculated? What is the formula for calculating strong suction?

According to powerful magnet Encyclopedia: the magnetic force of NdFeB magnet is 640 times of its own weight, that is to say, it can absorb 640 times of its own weight. Generally, NdFeB magnet can absorb objects 600 times of its own weight.

**Example**: the grade of square nd Fe-B magnet is: N35, specification is 30mm × 15mm × 5mm

Calculation formula of magnet suction: magnet volume × density × 600 (multiple)

- 1. Magnet density: the density of N35 is about 7.5G / cc. Read the density of magnets: ferrite, injection magnet, sintered NdFeB, bonded NdFeB density? 》
- 2. Weight of magnet: Volume × density (30mm × 15mm × 5mm) × 0.0075=16.875 G
- 3. Magnet suction: 16.875 × 600=10125g

It can be seen that a 30mm × 15mm × 5mm square magnet can absorb about 10.125kg of material.

Of course, this is just that the theoretical valuation may not be accurate, and the editor himself does not believe it. The accurate data must be obtained by practical experiments.

- Formula F = bisin theta

F is the magnetic force, also called ampere force. B is the magnetic induction strength, I is the current in the conductor, l is the length of the wire, and theta is the angle between B and the conductor.

Magnetic force formula of magnetic pole: F = MH, where m is the pole strength, h is the magnetic field strength, and the magnetic field strength produced by the pole is inversely proportional to the third square of distance R.