Amazon FBA Calculator UK: Can You Afford a Black Friday Deal?

A £3 discount on a product that earns £5 per order can be expensive even if sales double. Before setting a Black Friday deal price, run the same UK listing through the Amazon FBA calculator twice. Keep a copy of each result. The figure you need is the money left per unit to cover overheads after all the costs that change with that sale.

Set up the UK calculator for the item you will actually ship

Open the Revenue Calculator from Amazon UK’s pricing page. Select the UK store and look up the ASIN for the exact pack size. For a new product, enter the dimensions and weight of the packaged unit. Measure the box a customer receives. A single cable and a twin pack may look almost identical in the catalogue and occupy different fee tiers.

Enter the usual selling price and record the referral fee and fulfilment estimate. Add your landed product cost and any variable costs you bear outside that estimate, such as inbound transport per unit, preparation, advertising or an expected returns allowance. Check which costs the estimate already includes. Use the same VAT treatment across both scenarios and reconcile your inputs with your own records.

Check the festive fee before setting the discount

For certain FBA orders delivered to UK buyers, Amazon lists a festive peak fulfilment fee from 15 October 2026 to 14 January 2027. Eligibility depends on the item. Open the current fee preview for your SKU and check whether the seasonal amount is already included before adding anything by hand. Amazon’s festive fulfilment fee guidance.

Run a second estimate at your proposed deal price. A percentage referral fee may fall when the price falls, while the fulfilment cost of the same parcel can stay the same. Copy the new estimates into their own column. Include any separate promotion charge in the decision.

Calculate the units needed to break even on the deal

Suppose a seller retains £20 per normal sale on a consistent tax basis. Product and inbound cost total £9, estimated marketplace fees are £4 and other variable costs are £2. Contribution is £5 per unit. At a promotional net selling price of £17, assume marketplace fees fall to £3.60 while the other costs hold. Contribution becomes £2.40. These are illustrative amounts.

• Expected normal trading over the promotion dates is 40 units × £5 = £200 contribution.
• To match £200 at £2.40 each, the deal needs 84 units, rounding up.
• If there is also a £24 fixed deal charge, the target rises to 94 units: (£200 + £24) ÷ £2.40, rounded up.

Suppose the warehouse has 70 saleable units and no replenishment due in time. Selling all 70 at the deal price after the £24 charge leaves £144. The shortfall is £56 even with a sell-out. Try a smaller discount, shorten the promotion or keep the normal price. If the numbers do work, use the UK FBA shipment checklist to check that the stock can reach the fulfilment centre in time.