Free tool
Margin vs. markup calculator
Enter your cost and the margin you want to keep. Get the sell price that actually hits it.
Margin is the share of the sell price you keep. Markup is what you add on top of cost. They are not the same number: a 45% margin needs an 81.82% markup. If you mark up cost by 45%, you only keep a 31% margin. Price from margin, and the profit you planned is the profit you get.