How do I tell which SKUs lose money after returns are factored in?

Last updated: June 27, 2026

To find profit by SKU after returns, compute return-adjusted SKU margin: contribution per kept unit times kept units, minus net loss per returned unit times returned units, all divided by units sold. Apply each SKU's own return rate, not your store average. A SKU profitable on gross margin can turn negative once its returns are charged against it.

Why blended return numbers hide your losers

A store-level return rate averages your best and worst SKUs into one harmless-looking number. A 9 percent blended rate feels fine. Inside it, a fitted-apparel SKU returning at 30 percent and a phone case returning at 4 percent are both buried, and the apparel SKU may be eating the profit the case earns.

Return-adjusted profit means margin calculated after each returned unit's full round-trip cost is subtracted from the units that stayed sold. The cost of a return is not just the refund. A returned unit carries the original outbound shipping, the inbound return shipping, the payment processing fee you rarely recover, restocking labor, and any markdown or write-off if the item cannot be resold at full price. Charge those to the store average and they disappear. Charge them to the SKU that caused them and the picture changes.

That is the gap this post closes. Most SKU profitability reports stop at gross margin or contribution margin and never apply the SKU's own return rate. Below is a formula that does, plus a worked example where a product that looks profitable flips to a loss.

The return-adjusted SKU margin formula

Return-adjusted SKU margin is the per-unit profit of a SKU after its own returns are paid for by its own sales. Here is the formula in plain terms:

Return-adjusted margin per unit = (C × K − L × R) ÷ U

Where:

• U = units sold (gross, before returns)
• R = units returned
• K = units kept (U − R)
• C = contribution per kept unit (price minus COGS, payment fee, and outbound shipping)
• L = net loss per returned unit (every dollar that leaves on a return: refund net of recovered value, both shipping legs, the unrecovered payment fee, restocking labor, and markdown or write-off)

The logic is simple. Kept units earn contribution. Returned units lose money. Spread the net of those two across every unit you sold, and you get the true per-unit profit for that SKU. Run it SKU by SKU and your losers stop hiding.

Worked example: the $24 phone case two-pack

Take a phone case two-pack that sells for $24. On paper it looks like a winner. Watch what its own return rate does to it.

Step 1: Contribution per kept unit

Line	Amount
Selling price	$24.00
COGS (both cases plus retail box)	-$7.50
Payment processing (2.9% + $0.30)	-$1.00
Outbound shipping	-$5.20
Contribution per kept unit (C)	$10.30

A kept unit clears $10.30. Gross-margin math stops here and calls this SKU healthy, because $10.30 on $24 is a 43 percent contribution margin.

Step 2: Net loss per returned unit

A return reverses the good and adds new costs. The customer gets the $24 back. You eat the fees and the freight, and a returned two-pack often comes back opened, so it gets marked down rather than resold at full price.

Line	Amount
Refund issued	-$24.00
Outbound shipping (already spent, gone)	-$5.20
Return shipping (prepaid label)	-$5.80
Payment fee not refunded by processor	-$1.00
Restocking and inspection labor	-$2.00
Recovered value (resold at markdown)	+$12.00
Net loss per returned unit (L)	-$26.00

Every returned two-pack costs you $26.00 net. That is bigger than the $24 price, because the freight, fees, and labor stack on top of the partial refund recovery.

Step 3: Apply the SKU's own return rate

Say this SKU sells 1,000 units a month and returns at 18 percent, common for phone cases bought for fit and feel and sent back when they do not match the phone or look cheaper than expected. So U = 1,000, R = 180, K = 820.

Return-adjusted margin per unit = (C × K − L × R) ÷ U

= ($10.30 × 820 − $26.00 × 180) ÷ 1,000

= ($8,446 − $4,680) ÷ 1,000

= $3,766 ÷ 1,000

= $3.77 per unit

At 18 percent returns the SKU still earns $3.77 a unit, down from the $10.30 the gross-margin view promised. The returns ate 63 percent of the apparent profit.

Step 4: Find the point where it flips

Now push the return rate to where this SKU actually loses money. Set the numerator to zero and solve for R:

$10.30 × (1,000 − R) − $26.00 × R = 0

$10,300 − $10.30R − $26.00R = 0

$10,300 = $36.30R

R = 283.7 units, which is a 28.4 percent return rate

Above a 28.4 percent return rate, this $24 two-pack loses money on every unit it sells. At 30 percent returns it runs at roughly negative $0.55 a unit. A store reporting a 9 percent blended return rate would never see it, because the SKU's own 30 percent is averaged against everything that returns at 4 percent. That is the figure to take away: the break-even return rate for this SKU is 28.4 percent, computed from its own contribution and its own net loss per return, and it is invisible in any blended number. For the why behind that flip point, see our breakdown of the return rate where margin breaks even.

How do I find profit by SKU after returns in my own store?

Pull four numbers per SKU and run the formula above. You need units sold, units returned, contribution per kept unit, and net loss per returned unit. Here is the order of operations.

1. Get returns attributed to the right SKU

Match every return to the exact SKU and variant, not the order. Order-level return data lumps a returned shirt in with the kept socks on the same order and corrupts the rate. If your platform reports returns per line item, use that. If it only reports per order, you have a data problem to fix before any of this is trustworthy.

2. Build the full cost of a return, not just the refund

Add the refund net of recovered value, outbound shipping already spent, inbound return shipping, the payment fee the processor keeps, restocking labor, and any markdown. Skip these and you will understate the cost of every return by roughly the freight plus fees, which on a low-price SKU is most of the damage. Our note on why returns cost about double the shipping line walks through the legs people miss.

3. Compute contribution per kept unit

Price minus COGS, payment fee, and outbound shipping. Use real landed COGS including inbound duty where it applies. This is the same contribution-margin discipline that should already drive your pricing, applied per SKU.

4. Run the formula and rank

Calculate (C × K − L × R) ÷ U for every SKU, sort ascending, and the negative rows are your money-losers. Then segment further, because a SKU's returns often cluster in one channel or customer cohort. The same product can be profitable from one source and a loss from another, which is why margin by SKU, channel, and customer is the next cut to make.

What it costs to skip this

Skipping return-adjusted SKU analysis means you keep promoting your worst products. The SKU with the fat gross margin and the quiet 30 percent return rate looks like your hero, so you put it in ads, in bundles, on the homepage. Every incremental sale loses money, and your ad spend accelerates the bleed. You discover it at month-end, in aggregate, with no idea which SKU did the damage. By then you have paid for a quarter of unprofitable orders. Computing the number per SKU turns a vague margin worry into a list of products to reprice, rebundle, or retire this week. The full version of this discipline is in how to calculate true net margin end to end.

External benchmarks on category return rates vary widely and are often self-reported, so treat any single industry figure as directional only. The number that matters is your own, per SKU, computed from your own costs.

Where Agentis fits

Running this formula once in a spreadsheet finds today's losers. Keeping it current as return rates drift, freight changes, and new SKUs launch is the hard part, and that is where real-time profit governance earns its place.

Profit governance is the practice of monitoring and enforcing margin rules in real time across every order, SKU, and channel, so unprofitable activity gets caught and corrected as it happens instead of discovered in a month-end report.

Agentis is a real-time profit governance platform for high-volume Shopify Plus and ShopLine merchants. It monitors margin at the order and SKU level and flags or blocks unprofitable activity before it reaches the P&L. For a SKU like the $24 two-pack, that means you see the break-even return rate move past your real rate the week it happens, not the quarter after.

Frequently asked questions

What is return-adjusted profit by SKU after returns?

Return-adjusted profit by SKU after returns is a product's per-unit margin once its own returned units are paid for by its own sold units. Compute it as contribution per kept unit times kept units, minus net loss per returned unit times returned units, divided by units sold. The number reveals losers that gross margin hides.

Why does a SKU look profitable on gross margin but lose money after returns?

A SKU looks profitable on gross margin because gross margin only counts the units that stayed sold and ignores the cost of the ones sent back. Each return carries both shipping legs, the unrecovered payment fee, restocking, and markdown, which often exceed the item's price. Apply the SKU's own return rate and the apparent profit can flip negative.

How is net margin different from contribution margin for returns analysis?

Contribution margin is price minus the direct variable costs of a kept unit, which is the right input for the per-kept-unit term in the formula. Net margin goes further and nets out the full cost of returns and other variable losses across all units sold. For returns work you need both: contribution per kept unit and the net loss per returned unit.

What return rate makes a SKU unprofitable?

A SKU becomes unprofitable when its return rate passes the point where contribution from kept units no longer covers the net loss from returned units. Solve contribution per kept unit times (1 minus rate) equals net loss per returned unit times rate. In the $24 two-pack example that break-even rate is 28.4 percent.

Why are blended store return rates misleading for SKU profitability?

Blended store return rates average high-return and low-return SKUs into one figure that hides both. A 9 percent store average can contain a SKU returning at 30 percent that loses money on every sale. SKU profitability requires each product's own return rate applied to its own costs, never the store average.

Your next step

Pick your three best-selling SKUs, pull units sold, units returned, contribution per kept unit, and net loss per returned unit for the last 30 days, and run (C × K − L × R) ÷ U on each. If any come out lower than you expected, you just found where your margin is leaking.