Magnetic flux vs Magnetic flux density?Watch
Magnetic flux density is how much area that magnetic flux is present across.
For example: imagine you have two magnets,
Magnet A, which is smaller
And magnet B, which is bigger
These both are made of the same material and have the same magnetic flux.
However, because magnet B is bigger, it has a higher magnetic flux density than magnet A
Hope this helps
Magnetic flux is the product of magnetic flux density/ field strength and the area perpendicular to the field lines . If you like , magnetic flux is different in the sense that it involves some type of area . So field lines passing through an area
Scroll down to the image to see field /flux lines passing through an area