# Using Calculations with Flat Rate Shipping in WooCommerce

Recently I had a user that needed to charge a flat rate for shipping the first item and then a smaller amount for each additional item. It’s possible to set up this with Table Rate Shipping, but did you know you can also do some basic math with WooCommerce’s built-in Flat Rate Shipping? Let’s take a look at a quick example.

This user wanted to charge $29.90 for the first item in the order. Then for each additional item they wanted to charge and additional $9.90. How can we approach this?

First, we enter the $29.90 to cover the first item. To add to it, we use `+`

operator. Here’s where the math comes in. We need to group the next calculations together so we’ll wrap them in parentheses. Here’s what we have now.

`29.90 + ( )`

To cover each additional item we can add this `9.90 * [qty]`

which will add an additional 9.90 for each item in the cart. The `[qty]`

is a variable that represents the number of items in the cart. That gives us a basic equation like this:

`29.90 + (9.90 * [qty])`

There’s one significant issue with this. The first item will end up with a shipping charge of 39.80 instead of 29.90! Not good. We need a way to **not charge** the item cost on the *first* item.

To do that we need one more set of parentheses to modify the quantity. We can use the quantity variable and just subtract `1`

from it since the first item is covered by the initial 29.90 amount. That gives us a final equation like this:

`29.90 + ( 9.90 * ([qty] -1) )`

Now customers are charged $29.90 for the first item then an additional $9.90 for each item after that. With a little bit of practice you can use Flat Rate Shipping for some situations where you might think you need a full fledged Table Rate setup. If you have any creative uses for math with Flat Rate Shipping, share them with us in the comments.