Shipping to include tax

Hi,
I have tax calculating on shipping, but I'd like it to automatically calculate the tax.

eg.
At the moment I need to type in $10.43 and it will then add 15% to make $11.99 (aiming for a nice rounded $12 as well)
I would like to set it at $7 and have it calculate the amount for me.
(I have variable shipping that I quote for and create the orders myself very often each day)

When creating products I can type in the gross field, but not sure where to do that for this?
Thanks and sorry if it's obvious, but first time adding taxes.

I'd like to help, but I don't understand the question. It sounds like you are entering 10.43 as the product price and the 15% is tax. In the next sentence you use 'it' twice and I'm not sure what 'it' you're referring to. Can you clarify?

Thanks for helping.

I'll maybe bullet point...

• Need to charge tax on shipping
• Only use one zone for the whole country
• Want to input shipping cost as x in 'shipping modules' and have that amount show at checkout (inc 15% tax)
• We edit shipping all day, so want the amount we type in to include tax in 'shipping modules'
  (if not it means we have to calculate the amount, then type it in module and the cart brings it to our desired rounded figure)

Very tricky to explain sorry, but does that make sense?
Basically trying to avoid calculating each tax exclusive amount for every purchase....