Ebay / Amazon Profit Calculator - Making a Specific Margin after fees

Hi all,
I have just started selling on eBay and find it confusing to know how much I'm making. I don't want to appear too expensive or give my products away. If I have a part that costs me £20.00 plus vat i.e £24.00. I have to include carriage £5.00 plus vat i.e £6.00. Ebay fees for car parts including PayPal is 10%. How much would I charge to retain 20% percent after all fees and charges and what formula would I use to make the calculator. Any help would be, as always appreciated.
Best regards
Jason

Total cost to You say:- £33
Profit required + 20%

33 x 1.2 = 39.6 = Price to charge

Check
39.6-33/33 = 20%

Originally Posted by MickG

Total cost to You say:- £33
Profit required + 20%

33 x 1.2 = 39.6 = Price to charge

Check
39.6-33/33 = 20%

Hi Mick,
Thanks for that but I need to calculate all eBay charges etc.