Contribution profit answers a different question from cash flow
Contribution profit estimates what remains from an order after the variable costs assigned to that order. Cash flow tracks when money actually enters and leaves your bank account. A product can have positive contribution profit while your business is short of cash because you bought inventory in bulk, paid for advertising upfront or have not yet received a marketplace payout.
Keep these measures separate. Use contribution profit to compare products, channels and campaigns. Use cash-flow tracking to plan purchasing, payroll, taxes, debt payments and the timing of marketplace settlements.
Calculate contribution profit consistently
A practical order-level formula is:
Net sales = item revenue + shipping collected − discounts − refunds. Enter each of those amounts excluding sales tax, and record sales tax separately for reconciliation.
Contribution profit = net sales − product cost − inbound freight − packaging − fulfilment/postage − marketplace fees − payment processing − advertising − other variable costs.
Contribution margin = contribution profit ÷ net sales.
Worked example: one order
Assume an order has $50.00 in item revenue, $5.00 shipping collected, $5.00 discounts and no refund. Net sales are $50.00. If product cost is $14.00, inbound freight $1.00, packaging $1.00, fulfilment $5.00, marketplace fees $7.00, payment fees $1.50, advertising $4.00 and other variable costs $1.00, contribution profit is $15.50. Contribution margin is 31% ($15.50 ÷ $50.00).
This is not the same as final business profit. It does not include fixed overhead unless you deliberately allocate it, and it does not include income tax, financing costs or owner distributions.
Why cash can move in the opposite direction
- Inventory timing: you may pay a supplier weeks before the related products sell. A bulk purchase can consume cash even when each eventual order has a positive contribution.
- Marketplace settlement delays: sales may be recorded before the payout reaches your bank. Reserves, refunds and adjustments can change the amount and timing.
- Advertising timing: ad platforms may charge daily or weekly, while the orders attributed to those ads settle later.
- Returns and refunds: a refund can create a cash outflow after the original order was counted. Returned inventory may also be damaged or unsellable.
- Taxes and debt: sales tax collected for authorities is not operating revenue, and loan principal payments affect cash even though they are not a variable order cost.
A simple monthly review routine
- Review contribution profit by SKU and sales channel using actual marketplace fees and supplier costs.
- Reconcile marketplace payouts to bank deposits, refunds, reserves and fee adjustments.
- List upcoming cash obligations: inventory deposits, freight, advertising, subscriptions, taxes and debt payments.
- Estimate how much cash is tied up in unsold inventory and how long it takes to convert stock into settled funds.
- Update assumptions when return rates, ad costs, carrier prices or platform fees change.
Use the right tool for each question
Use the product profit calculator to model one order, then record actual results in the free order profit tracker. For pricing decisions, start with the target selling price calculator. None of these replaces a cash-flow forecast or your accounting records.
Common mistakes to avoid
- Counting sales tax as revenue and then subtracting it again.
- Mixing payout date with order date without labelling the difference.
- Counting the same fulfilment or marketplace fee in two cost fields.
- Calling contribution profit “net profit” when fixed overhead and other expenses remain.
- Using forecast estimates instead of reconciling against actual statements.
Consistent definitions matter more than a complicated spreadsheet. Start with the costs you can verify, label estimates clearly and reconcile regularly.