A $75 free-shipping threshold is a checkout rule. It is not a margin guarantee. Before a holiday promotion goes live, ask your fulfillment partner to price the baskets that will qualify, including the awkward ones.
The decision is whether the offer works across your likely order mix. A store-wide average can hide the products that consume most of the shipping subsidy.
Start with the amount that actually qualifies
Shopify says a free-shipping discount's minimum purchase amount uses product prices, excludes taxes, and takes combinable product discounts into account. Gift cards purchased in the cart also count toward that minimum. Check your exact promotion settings with representative carts before promising an offer. Shopify's free-shipping documentation.
For the margin analysis, separately identify physical products, gift cards and other items with different cost treatment. A qualifying checkout total should not automatically become your physical-goods revenue input.
Two equally valuable baskets, very different room for shipping
Our illustrative calculation uses two invented baskets with $75 of net physical-product revenue each. Neither is a customer order or a provider quote. Transportation is an assumed total; do not add fuel a second time if it is already included.
| Per order | Compact basket | Bulky basket |
|---|---|---|
| Net product revenue | $75 | $75 |
| Product cost | $30 | $42 |
| Warehouse work and packaging | $4 | $6 |
| Transportation, including assumed applicable fees | $8 | $18 |
| Contribution before other costs | $33 | $9 |
| Contribution with another $2 transportation expense | $31 | $7 |
The calculation is revenue minus the three cost lines. Marketing, payment processing, returns, overhead and taxes are excluded, so these results are not net profit. The $2 sensitivity is a hypothetical stress test, not an announced carrier charge.
Both baskets pass the same threshold. The bulky order has far less room for an unexpected charge. Raising a threshold without examining which products customers add could leave that problem intact.
Put dated fees into the right cost line
As checked September 29, DHL eCommerce's U.S. table lists domestic fuel at $0.29 per pound for September and $0.30 for October 1–31, 2026, with a one-pound minimum for packages below one pound in chargeable weight. Its peak surcharge is listed separately. This is DHL eCommerce, not DHL Express. Official surcharge policy.
Ask the 3PL which contracted rates, chargeable weights and pass-through rules apply. Do not apply those published figures to another carrier or assume they equal your invoice.
Approve a promotion with boundaries
Give the 3PL a small basket file grouped by product family, packed dimensions, destination and expected ship week. Request transportation and warehouse charges separately. Then test a compact order, a heavy order, a remote destination and a discounted basket.
Set an internal minimum contribution target and identify which cases miss it. Possible responses include changing eligible products, limiting destinations, changing packaging or revising the offer. Test customer-facing wording alongside checkout behavior so exceptions are visible before payment.
Our recommendation: approve the offer only when the fragile cases have an owner and an agreed response. A larger cart is useful only if the additional revenue supports the additional work.
Related reading
Sources
Accessed September 29, 2026. Recheck platform and carrier terms before publication.