How to Auto-Tag Bestseller Products on Shopify by Units Sold

Yes — Shopify offers a 'Best selling' sort order on collection pages, and it's genuinely useful for arranging products by how well they've sold recently. But a sort order is a runtime calculation Shopify applies when a page renders, not a fact stored on the product — there's nothing to filter, export or save. A theme badge that reads 'Bestseller' on a product card, a saved admin search like tag:bestseller, an email segment built around bestselling products, or a Shopify Flow workflow all need something they can check per-product directly, and a sort order gives them nothing to key off — it only ever describes the current page's ordering, never an individual product's status. A tag is the opposite: a stored fact on the product record itself, so every one of those tools can read it the same way they'd read any other tag, without knowing anything about how Shopify computes its sort.

This rule works off an absolute units-sold threshold you choose yourself — say, 50 or more units — rather than a ranking relative to the rest of your catalogue. That's a deliberate difference from Shopify's own 'Best selling' sort, which IS relative: it always has a #1, even in a ten-product catalogue where nothing is actually selling well. An absolute threshold means the tag is a fact about that one product's own sales record, not a moving target that shifts depending on what else you happen to be stocking that month. You can still approximate a relative feel by picking a threshold near where your own top slice of products historically sits, and revisiting it as your catalogue and sales volume grow — but the rule itself always evaluates the same fixed number, so what 'bestseller' means on your store doesn't quietly drift without you deciding it should.

Yes — the same rule shape works over any window you choose: the last 30 days, the last 90 days, or all time, and nothing stops you running more than one at once, each with its own threshold. A 'trending now' tag on a 30-day window catches a product that's suddenly taking off — a seasonal item, something that went viral, a restock that sold through fast — while an 'all-time bestseller' tag rewards a product with a genuinely long sales history, even if this particular month is quiet for it. The two tell different stories and usually deserve different thresholds too: a 30-day window naturally needs a lower bar than all-time, since there's simply less time for units to accumulate. Because each window is its own independent rule, changing the threshold on one — tightening 'trending' for a big sale event, say — never touches how the all-time tag behaves.

That depends entirely on which window the tag is built from. Units sold ALL TIME can only ever increase — a product that has sold 200 units in its lifetime has still sold 200 units next month even if it sells zero more, so an all-time bestseller tag never needs removing once it's earned. A last-30-days tag behaves completely differently, because the window itself moves: even with zero new sales, a product's 30-day count quietly drops every day as older orders roll out of the window and nothing new replaces them. A rule built on that window should re-check the condition regularly and remove the tag the moment a product's recent sales fall back under the threshold — otherwise a 'Trending now' badge keeps pointing customers at something that stopped trending three weeks ago, which is exactly the kind of stale, manually-maintained badge this rule is meant to replace.