How to calculate shipping for cart total weight with slab rate?

Need to arrive cart weight and based on the shipping slab rate, cart shipping charge to be determined.

My cart – 1) Coir – 5.05Kg 2) Vermicompost – 10.05kg = Total cart weight = 15.10 kg

Shipping slab: Upto 2 kg = Rs. 45; For every additional 1 kg upto 5Kg =Rs.12/kg; For every additional 1 kg above 5 Kg = Rs. 14/Kg

How to arrive formula. I use default woocommerce shipping not installed any other plugin. pls guide. i have enabled shipping class 0-5 kg for coir and 10kg for vermi.