The Inventory Replenishment SOP for Shopify DTC Brands

Your best-selling SKU went out of stock on a Tuesday in the middle of a good week. The ads were still running, still sending traffic to a product page with a grayed-out add-to-cart button, and you found out when a customer emailed asking when it would be back. Meanwhile three shelves over you have eight months of a color nobody wants, and that is cash you cannot spend on the thing that actually sells.

This is the replenishment problem, and almost every growing DTC brand runs it the same way: someone eyeballs the Shopify inventory screen every so often, gets a bad feeling about a number, and fires off a purchase order. It works until it does not, which is usually the exact moment it matters most, during a sales spike or right after a supplier's lead time stretched by three weeks and nobody noticed.

There is no shortage of articles telling you the reorder point formula. This is not that. The formula is one line. The hard part, the part that actually keeps you in stock without drowning in dead inventory, is the repeatable process around it: who watches which SKUs, what number triggers an order, who is allowed to spend the money, and how you keep the whole thing from going stale as your sales change underneath it. This is the SOP for that.

Why replenishment is a process, not a formula

Search 'reorder point' and you will get fifty near-identical posts from inventory software companies, each handing you the same formula and a calculator. The formula is real and you will use it. But a formula is not a process, and inventory does not stock itself out because someone got the arithmetic wrong. It stocks out because nobody was assigned to run the arithmetic on a schedule, or because the number was right in March and nobody revised it for the summer.

A replenishment SOP answers the questions the formula does not: how often does someone check, which SKUs get watched closely versus loosely, who raises the purchase order, who signs off on the spend, who chases the supplier when the ship date slips, and who updates the expected arrival date in Shopify so the rest of the team is not planning around a fantasy. Get those owners named and the formula becomes the easy part.

The number everyone gets wrong: total lead time

Here is the single number that breaks more DTC replenishment than any other: lead time. When your supplier says 'we ship in three days,' that is not your lead time. That is the day they hand it to a carrier. Your real lead time is every day between placing the order and having sellable units on a shelf you can pick and pack.

For an overseas supplier, three days of production becomes fourteen days or more once you add ocean freight, port and customs processing, the drive to your warehouse or 3PL, and your own receiving and put-away. Plug three into your reorder math instead of fourteen and you will set a reorder point so low that you place the order the week you should already be receiving it. The stockout is baked in before you sell a single unit.

And do not use your average lead time. Use your realistic worst case. A supplier who averages seven days but hit eighteen once during Chinese New Year will do it again next year, and the whole point of the buffer is to survive the bad case, not the typical one. Measure your total lead time honestly, per supplier, and write it down. It is the most important input in the entire process and the one nobody bothers to get right.

The trigger: reorder point, or weeks of cover

Once you know your true lead time, you need a trigger: the stock level that says 'order now.' The classic version is the reorder point.

Reorder point = (average daily sales x total lead time in days) + safety stock. If you sell 10 units a day, your total lead time is 14 days, and you want 7 days of safety stock, your reorder point is (10 x 14) + (10 x 7) = 210 units. When that SKU hits 210, you order.

That works, but it is static, and your sales are not. A better trigger for a growing brand is weeks of cover: how many weeks the current stock will last at the current sales rate. Reorder when your weeks of cover drops below your total lead time plus a buffer. The advantage is that it adjusts on its own as velocity changes. A product that starts selling twice as fast burns through its cover twice as fast and flags itself for reorder earlier, with no one having to remember to update a fixed number.

Safety stock is the buffer that absorbs the days your sales spike or your supplier runs late. How big it should be depends on your service level, the percentage of the time you want to avoid a stockout. A 95 percent service level uses a safety factor of about 1.65 times the variability in your demand and lead time. Here is the DTC-specific lever most guides miss: because you own your storefront, a stockout does not carry the marketplace penalty an Amazon seller eats. You can show an out-of-stock badge, capture emails for a restock alert, and often recover the sale. That means you can run a slightly lower service level, say 94 to 96 percent, hold less safety stock, and free up the working capital that would otherwise sit frozen on a shelf.

The replenishment SOP, step by step

Here is the routine. Run it weekly. The whole thing takes under an hour once your lead times and triggers are set, and that hour is the difference between reordering on time and reordering in a panic.

1. Pull sales velocity for every active SKU, in units per day over the last 30 to 60 days.
2. Calculate weeks of cover for each: current on-hand divided by the weekly sales rate.
3. Flag every SKU whose cover has dropped below its total lead time plus buffer.
4. For each flagged SKU, calculate the order quantity, respecting the supplier's minimum order quantity and your cash position.
5. Raise the purchase order with full details, and route it for spend approval.
6. Send the PO to the supplier and confirm the ship and arrival dates.
7. Update the expected arrival date on the SKU in Shopify so everyone downstream is planning around the real date.

Segment your SKUs so you are not watching all of them equally

You cannot give 300 SKUs the same attention, and you should not try. Segment by revenue. Your A items, the top 20 percent of SKUs that drive most of your revenue, get watched closely and never allowed to run thin. Your C items, the long tail at the bottom, get a looser trigger and a bigger tolerance for a short stockout, because tying up cash to keep a slow mover perfectly in stock is a bad trade. This is where you spend your safety-stock budget deliberately instead of spreading it evenly and running out of the things that matter.

Name the five owners

A replenishment process fails at the handoffs, so name them. Five roles, and on a small team one person may hold several, but each must be assigned to a name:

• Who monitors cover and flags the SKUs each week.
• Who calculates the order quantity and raises the purchase order.
• Who approves the spend, especially past a dollar threshold, so a large buy is not placed on autopilot.
• Who chases the supplier when a ship date slips, because it will.
• Who updates the expected arrival date in Shopify so support, marketing, and finance are not planning around a date that moved two weeks ago.

A complete purchase order, for the record, carries a PO number, the supplier details, each line item by SKU with quantity and unit cost, the order total, the requested delivery date, the shipping method, and the payment terms. A shared sheet handles this fine until you are juggling more than a handful of open POs across several suppliers.

The five mistakes that cause stockouts

Nearly every DTC stockout traces to one of these five, and only one of them is about math:

1. Using the supplier's quoted ship time instead of your total lead time, so you reorder weeks too late.
2. Using average lead time instead of your realistic worst case, so the first supplier delay empties the shelf.
3. Setting reorder points once and never revising them, so a product that doubled in velocity keeps flagging at its old, too-low number.
4. No named owner, so the weekly check happens when someone remembers, which is usually the week after they should have ordered.
5. Ignoring minimum order quantities and payment terms, so the quantity your formula says to order is not one your supplier will accept or your cash can cover this month.

Notice that four of the five are process failures, not calculation failures. The formula is almost never the problem. The problem is that nobody owns running it on time, with honest inputs, and revising it when the business changes.

Why reorder points rot

A reorder point is a snapshot of a moment: this SKU's velocity, this supplier's lead time, this season. Every one of those moves. A product gets a viral moment and triples in velocity. Peak season arrives and your daily sales double for eight weeks. You switch to a cheaper supplier whose lead time is three weeks longer. You add a subscription and now a chunk of demand is predictable and recurring. Each change makes the old reorder point wrong, and the number does not announce that it has gone stale. It just quietly sends the order too late.

This is SOP drift in its most expensive form, because a stale reorder point looks like a working system right up until the shelf is empty. Documented and wrong is worse than undocumented, because it stops you from checking. Revise your reorder points and lead times on a schedule, monthly for your A items, and immediately whenever a supplier changes or a product's velocity shifts hard. A replenishment SOP that is never revised is just a slower way to run out of stock.

Where to start this week

Do not try to systematize 300 SKUs on Monday. Take your top 10 by revenue, the ones a stockout actually hurts. For each, write down two things: your honest total lead time, and the name of the person who will check its cover every week. That is a working replenishment SOP for the SKUs that matter, and you can expand it from there.

Then calculate weeks of cover for those ten today. If any is already below its total lead time, you are late, and now you know it instead of finding out from a customer email.

The hard part was never the formula. It is capturing the judgment your ops person carries in their head, the real lead times, the suppliers who slip, the SKUs that spike, and keeping that record honest as it all changes. That is the problem we built ReccordSOP to solve. Record how your team actually runs a reorder cycle once, and ReccordSOP turns it into a step-by-step SOP anyone can follow. When a supplier changes or a product's velocity shifts and a step goes stale, drift detection flags it before it turns into an empty shelf during your best week.

Record your next reorder cycle once and generate the SOP free at reccordsop.com.