Cutting bottom of door- Jigsaw/Circular/Plane?

[outmyway]

I need to cut 18mm off the base of my bathroom door - what should I use for this?

Its a modern solid MDF type .... I'm worried about shreading around where the blade goes...

 

[big-all]

only use a jigsaw if you know it will cut strait

use a circular saw and batton score the opposite side and trailing edge with a stanly knife
set the saw blade to 2mm sticking through 'clamp the batton on so the larger part off the base plate is supported

 

[outmyway]

Thanks big-all .... why set the blade to only 2mm sticking through? Should that read 2cm???

 

[big-all]

no one tooth so when the tooth breaks the surface its mostly pushing forward
rather than pushing down and possibly chipping the surface