vba if statements based on weight and fee calculation

Hi,
I am trying to find out how i can set up if statements based on parameter values. For example;

My function will be "Shippingfees" based on the parameter weight

Shipping fee is calculated based on weight.
If it is 1 pound, shipping fee is $2
If it is 2 pounds, shipping fee is $4
After two pounds, fee is increasing by $1 for every pound. But if the weight is 2.3 pounds this will still be based on 3 pounds. So it actually means if weight>2 and weight<=3 fee will add up one more dollar.
If it is , let 's say 5.3 pounds, then the fee will be 8 dollars ($4 + $1 + $1 + $1 + $1) [because it will be recognized as 6 pounds]

My question is how can i set up this in vba?
I'd very much appreciate if anyone could help.
Thanks

Hi,
Thanks for your reply. But i will be expanding it creting other functions and conditions. The fee calculations are a small part of this and I will be using too many if statements embedded in these fee calcualtions. The size of the file will be huge slowing down the processing if i use only excel . I'd be better off setting this up in vba which will make it a lot faster. Thank you