Free Shipping Break-Even Calculator

How the number is derived

The free shipping threshold has to be set so that the extra contribution from a larger basket covers the shipping being given away. Break-even threshold ≈ current average order value + (shipping cost ÷ contribution margin rate).

The division is the part that surprises people. Giving away $9.85 of shipping at a 55% contribution margin requires $17.91 of additional revenue, not $9.85, because only 55 cents of each extra dollar is contribution.

An example

Current AOV $58, contribution margin 55%, shipping $9.85. The break-even threshold is 58 + (9.85 ÷ 0.55) = $75.91, so a $75 or $79 threshold.

Check it. An order at $75 generates $41.25 of contribution; subtract $9.85 of shipping and $3.35 of packaging and labour and $28.05 remains. An order at $58 with the customer paying shipping generates $31.90 less $3.35, $28.55. Near enough identical.

So a $75 threshold breaks even only if it actually lifts orders from $58 to $75. If half the customers who cross it would have spent $70 anyway, the threshold is giving away shipping on those orders for $5 of incremental revenue, and it loses money.

What the number hides

It assumes every order crossing the threshold was lifted by it, and most were not. The honest calculation splits customers into those who increased their basket to qualify and those who would have crossed it regardless, and only the first group generates the incremental contribution.

It also ignores the conversion effect, which runs the other way. Free shipping raises conversion across the board, and that gain can exceed the subsidy even when the basket-lift arithmetic looks marginal.

What this changes

Set the threshold from the order value distribution rather than from the average. The right place is just above a cluster of existing orders, so the customers sitting at $62 have a reason to reach $75, and far enough above that the ones already at $80 are a small share.

Then test it. Two thresholds run against split traffic for a month gives a direct answer on both basket lift and conversion, which no amount of modelling produces reliably.

Making the threshold work harder

Showing progress toward the threshold, with a line reading "add $13 for free shipping", substantially increases the share of customers who lift their basket, because the arithmetic is done for them at the moment it matters.

Recommending specific items that close the gap works better still, particularly high-margin accessories. A customer $13 short who is shown a $15 item at 70% margin contributes $10.50 rather than the $7.15 the general contribution rate assumes, which changes the break-even materially.

The threshold should also be reviewed whenever AOV or shipping cost moves. A threshold set two years ago against a $48 AOV and an $8 parcel is doing something quite different today, and because it keeps working in the sense of being crossed, nothing draws attention to the fact that it has stopped paying for itself.

The threshold does not have to be a single number across the catalogue. Heavy or bulky products can be excluded from the policy, or carry their own higher threshold, without changing anything for the majority of orders.

Most platforms support this through shipping profiles, and it removes the specific orders where the subsidy exceeds the contribution, which is where nearly all the loss from a free shipping policy is concentrated.