Start with the true unit cost
Include the costs that genuinely rise when you make or fulfil another sale: materials, direct labour, packaging, payment fees and fulfilment where relevant.
Work backwards from margin
If you want a 30% gross margin, dividing cost by 0.70 gives the required ex-VAT selling price. Adding 30% to cost would produce a 30% markup, not margin.
Reality-check the result
A mathematically correct price still needs to fit the market. Compare the result with competitor prices, customer value, capacity and the contribution required to cover overheads.
ProfitMaths guides provide general educational information, not personalised accounting, tax, legal or financial advice.