Most stores pick their free shipping threshold by rounding up. Average order value is $48, so the banner says free shipping over $50. Then nothing changes, and the merchant decides thresholds don't work.

The problem is the average. Export your last few hundred orders from the Orders page and look at the spread instead. Almost every store has a cluster where most orders actually land, and an average sitting inside it, pulled around by a handful of large orders. Set the threshold just above the top of that cluster, not above the average. If most orders land between $35 and $55, then $50 is already free for half your buyers, and $65 is the number that asks for one more item from people who were going to buy anyway.

Two things decide whether it works.

Check the gap against your cheapest add-on. If your smallest product is $12 and the customer is $30 short, the threshold is a wall, not a nudge. It has to be crossable with one realistic addition.

Show the remaining amount, not the rule. "Free shipping over $65" is a policy. "You're $9 away from free shipping", updating in the cart drawer as they add, is an instruction. Most themes already have somewhere to put this in the cart drawer section.

Then leave it alone for a month or two. Order value moves slowly, and a threshold that changes every week teaches your repeat customers that the number is arbitrary.

Ecom Swift LLC, a certified Shopify Partner since 2018.