Markup and margin answer different questions
A service costing 100 and selling for 150 leaves a difference of 50 in the same currency. Markup is 50 ÷ 100 = 50%; margin is 50 ÷ 150 = 33.3%. These figures exclude other costs unless you include them. Calling a 50% markup a 50% margin overstates the result.
Build the complete cost
Start with the supplier charge converted into your selling currency. Add fixed payment charges, support allocated to the order, and other known costs. A percentage fee on your selling price must be separate because it rises with price. Do not add a fee twice if already included in the converted cost.
A worked example
Hypothetical amounts: service cost 100 KES, support allocation 15 KES, and fixed payment fee 5 KES give a fixed cost of 120 KES. With a 3% fee on selling price and a target 20% contribution margin, the price is 120 ÷ (1 − 0.03 − 0.20) = 155.85 KES rounded up to cents.
The variable fee is about 4.68 KES and contribution about 31.17 KES. Contribution is not net profit: taxes, other overhead, refunds, and omitted costs still matter. When fee percentage plus target margin reaches 100%, this formula cannot produce a valid price.
Use the calculator
The calculator below uses one currency at a time. Enter converted supplier cost, fixed fees, allocated support cost, percentage fee, and desired contribution margin. It estimates a price; it does not quote live service rates or submit orders. The downloadable worksheet uses the same assumptions and explains markup.
Allow for changing costs
Record the rate and conversion assumptions behind a quotation and set an appropriate validity period. Recheck supplier costs before accepting the order. Include any reserve for corrections explicitly; refill is not guaranteed reimbursement. Read the support terms before promising remedies.
Review actual results
Replace estimated fees and support costs with what you incurred. Compare orders needing support with those that do not. A high headline markup can leave little contribution on small orders. Keep deposits separate from service revenue so spending a funded wallet does not count the same money twice.