What size MDF for this size and shape

[VioletG]

Hi,

What size piece of MDF should I get to create the shape and size?

The max width I can find is 2200mm , so will it need to be created out of two pieces?

Just wondered how you would go about this. It's to replace a damaged side of a staircase.

Thanks

 

[foxhole]

Raise the skirting a little or add a little trim and you can get out of standard sheet 8’x4’.

 

[RrogerD]

That's a very shallow staircase.
Personally, I'd use 6mm ply rather than mdf. It is stronger and imo, gives a better finish, assuming you countersink, backfill and sand the screw holes plus, prime, undercoat and gloss (sanding between coats).