Calculate a multi-buy offer before announcing it

A multi-buy offer changes both the selling amount and the basket structure. Calculate the complete promoted basket rather than multiplying the single-item margin and hoping extra volume compensates.

The figures here are hypothetical. Replace them with your own costs and applicable fees before making a pricing decision.

Start with the ordinary unit

Suppose one item sells for ₹300 with defined variable cost of ₹180. Contribution is ₹120 before fixed and excluded expenses.

Three separate units at ordinary price would produce ₹900 revenue and ₹360 contribution on that simplified boundary.

Keep the ordinary comparison genuine. Do not use a reference price that customers could not actually pay for the same item.

Calculate the proposed offer

For “three for ₹750,” revenue is ₹750 while the three stated item costs total ₹540. Contribution becomes ₹210.

The offer reduces contribution by ₹150 compared with selling all three at ordinary price, before any genuine shared-cost changes.

A larger basket than one unit does not automatically make the offer better than the alternative purchase pattern.

Add shared costs once

If the ₹180 unit cost excludes an outer package costing ₹30 per order, subtract that once from the promoted basket. Contribution then becomes ₹180.

If the original cost already included packaging, do not subtract the same amount again.

Write the boundary clearly so another person can reproduce the result. Per-item and per-order costs behave differently.

Consider what the buyer would otherwise do

Some customers might buy one unit; others might already buy three. The promotion's incremental effect differs between those groups.

Do not assume every promoted basket represents three entirely new sales. You may not be able to measure the alternative precisely, so use scenarios.

A useful offer can still reduce contribution from some orders. The decision needs the overall objective and observed result.

Check mixed-product eligibility

If the offer allows different products, calculate a lower-contribution valid combination. The same selling price can produce very different costs.

Do not test only three copies of the cheapest item to fulfil.

If certain combinations are excluded, state that plainly and confirm the storefront enforces it before promotion.

Inspect quantity boundaries

Test two, three and four eligible items. Determine whether the offer applies once, proportionally or according to another stated rule.

A customer should not have to guess how the fourth item is priced.

Also test an eligible and ineligible item together. A correct banner does not prove the basket calculation matches the intended offer.

Include returns and corrections in the record

Keep the realised price and promotion associated with the accepted order. Later support should not reconstruct it from a campaign that has ended.

Any adjustment follows the applicable policy and circumstances; obtain appropriate advice for the terms you use.

The operational requirement is an accurate original record, not a vague note that a discount happened.

Check stock and production capacity

A multi-buy campaign can consume stock faster even when order count changes little. Confirm that availability reflects the units required.

For made-to-order goods, more units also mean more work. Do not treat an order-level count as a complete capacity measure.

Pause or limit the offer when the fulfilment promise cannot be maintained.

Check a quantity change after selection

Remove one item from a promoted basket in a safe test and inspect the revised price. If the remaining quantity no longer qualifies, the interface should explain the new amount before confirmation. Keep the customer in control of that choice rather than silently charging an offer they did not intend to accept.

Review the actual basket contribution

After a controlled run, compare realised prices, product mix and costs with the model. Include additional packing or support work that the offer created.

Do not judge the result by revenue alone. A busy campaign can leave less contribution than an ordinary week.

A sound multi-buy offer gives customers a coherent reason to buy together while retaining an acceptable economic result. The arithmetic should be checked before the banner, not after the orders arrive.