Inventory how-to

How to know when your inventory spreadsheet is no longer enough

Your spreadsheet stops working when you spend more time updating it than using it, or when it leads to stockouts and overstock you only notice after the fact.

Short answer: Your spreadsheet stops working when you spend more time updating it than using it, or when it leads to stockouts and overstock you only notice after the fact. If you have more than a couple hundred SKUs, multiple suppliers with different lead times, or more than one person touching the sheet, it is probably already costing you sales.

Signs the sheet is breaking down

You find yourself reordering by gut feeling because the sheet is a day or two out of date by the time you check it. Sales happen faster than you can update rows, so the numbers you are looking at are already wrong.

You discover a stockout only when a customer asks about it, or you discover overstock only when cash is tight and you realize three suppliers' worth of inventory is sitting in a back room. Both are symptoms of a system that tells you what happened, not what to do next.

Signs the workload has outgrown it

Someone has to manually check sales velocity, lead times, and case pack sizes for each SKU before placing an order. As your SKU count grows, this turns into hours every week, and it is the first task that gets skipped when things get busy, which is exactly when mistakes happen.

You have formulas that break when someone adds a column, or a second person edits the sheet and overwrites someone else's work. If you cannot say with confidence who last updated the reorder numbers, the sheet has become a liability, not a tool.

Signs your suppliers are the bottleneck

You are tracking different lead times and minimum order quantities for each supplier in your head or in sticky notes next to the monitor. If you have more than two or three suppliers, this is hard to do reliably in a spreadsheet without a lot of manual upkeep.

You place orders late because nobody set a reminder, or you order the wrong quantity because the case pack size changed and nobody updated the sheet. These are small errors individually but they add up to cash tied up in the wrong stock.

Step by step

  1. List how many SKUs you track and how many suppliers you order from
  2. Time yourself doing one full reorder cycle, from checking stock to sending the PO
  3. Count how many stockouts or emergency reorders happened last quarter
  4. Check if anyone other than you can run the reorder process without help
  5. Note how often you catch a math or copy-paste error in the sheet
  6. If any of these point to a problem, test a tool that automates the forecast and order-by dates for a month and compare the time spent

Worked example

A store with 40 SKUs and one supplier can usually run fine on a spreadsheet, updated weekly, with a simple reorder point formula. The same store at 300 SKUs across six suppliers, each with different lead times and minimum order quantities, often finds the weekly update takes four or five hours and still misses things. If daily sales for a SKU are 3 units, lead time is 14 days, and safety stock is 5 days, the reorder point is 3 x (14 + 5) = 57 units. Multiply that kind of calculation across hundreds of SKUs and suppliers, done by hand, and errors become routine rather than rare.

How SteadyShelf helps

SteadyShelf replaces the manual side of this: it forecasts sales per variant, calculates the order-by date per SKU using each supplier's lead time and safety days, and rounds quantities to case packs automatically. It does not handle per-location forecasts, bundles, or landed cost, so if those are your main pain points a spreadsheet or a different tool may still be part of your setup.

$29/month flat, unlimited products and suppliers, 30-day free trial. Run the numbers now with the free reorder point calculator.

SteadyShelf is launching on the Shopify App Store. Join early access to get the install link first.

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FAQ

Is there a SKU count where a spreadsheet definitely stops working?

There is no fixed number, it depends on your supplier count and how often prices or lead times change. As a rough guide, once you are managing more than a handful of suppliers or spending several hours a week on reorder math, the spreadsheet is likely slowing you down.

Can I keep using a spreadsheet alongside a forecasting tool?

Yes, many stores keep a spreadsheet for notes, supplier contacts, or cash flow planning while using a tool for the forecast and order-by dates. The key is not relying on the spreadsheet for the actual reorder math once your SKU count grows.

Let SteadyShelf do this math for every SKU

Order-by dates per supplier, seasonal forecasts and draft POs for your Shopify store. $29/month after a 30-day free trial.

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