Maximum detectable distance between magnet and magnetometer

[siavosh1]

Hi Dear,
I have a single-component (Z-Axis) magnetometer with 60nT resolution.
I want to calculate the maximum distance that this magnetometer can detect an N52 magnet with a volume of 1 cm³.
So I used the following formula and inserted the values, and finally calculated the Z:

https://forum.allaboutcircuits.com/attachments/blockequation-png.257032/
Br = 1.47 T (for Magnet N52)
B= 60 nT (magnetometer resolution)
L=W=D=10mm
Z=?
My answer => Z= 1.579 m
Keep in mind that I intended to solve this problem in the simplest possible way; the angle of view of the magnetometer is perpendicular to the magnet plate.
https://forum.allaboutcircuits.com/attachments/blockmagnet-png.257033/
My question is whether I have chosen the right formula? or do you suggest another solution for it.

 

[Baluncore]

Welcome to PF.
Where did you get that block equation from ?

 

[siavosh1]

Welcome to PF.
Where did you get that block equation from ?

thank you for your reply,
I find it here :
https://crocus-technology.com/basic-magnetic-field-calculator/

 

[siavosh1]

Does anyone have any idea about this?

 

[Baluncore]

There is no reference with the calculator to the source of the equation linked.
The formula is of a different form to that normally given for a bar magnet.
It may be correct. It may simply be a different numerical approximation.
Google; magnetic field due to bar magnet on axial line

 

[sysprog]

It's important to recognize that the magnetic force varies in inverse proportion to the cube of the distance.