There is no stsandard calculation for a "14 foot kayak".
It depends on the type of construction.Glass on seams only? Glass on hull? Outside? Inside? Glass on deck? What weight of glass? Have you ever done anything like this before? Do you know the difference between an exposed weave lamination and a filled lamination?
You didn't give us the name of your design. If you are designing a one-off you will probably need twice as much.

: I am working on gathering supplies for a stitch and glue kayak and
: need to know how much resin and hardener I may need. 14 foot
: boat. This is my first attempt and want to have enough material
: but not a lot of waste. Thanks