Ivy's got a handy tool which you can use if you know the total selling price you want to charge your client, but you don't have a fixed percentage markup. Ivy's markup calculator allows you to input your target price for a line item and then Ivy calculates the exact markup percentage for you.
While you're working in a proposal or invoice, enter in your cost for a line item and then click the little blue calculator under the Markup field. This will open a little window where you should enter your target price per unit, then click "set markup":
The system will then calculate the markup percentage for you and the line item total will be the target price you had entered.
What if I'm calculating for a quantity greater than 1?
Since you're doing a multiple quantity line item, you're first going to need to use the markup calculator to calculate the markup percentage based on a quantity of 1. So you would start by making the quantity 1, enter the price per unit in the cost field, and then in the markup calculator you will enter the target price for 1 unit (take your total target price and divide by the desired quantity). This will calculate the markup percentage for quantity of 1. Then you can change the quantity to the desired quantity and it should bring the total up to your desired total.