Build one row per SKU with columns for on-hand units, inbound units, average daily sales, lead time, and cost. Then add two formulas: days of supply (on-hand divided by daily sales) and a reorder flag (that turns on when days of supply falls below your lead time plus a buffer). Update the on-hand and sales figures from your Seller Central reports on a set cadence, and act on the flags.
What columns should an Amazon inventory spreadsheet have?
At minimum: SKU, product name, units on hand, units inbound, average daily sales (velocity), lead time in days, landed cost, days of supply (a formula), and a reorder flag (a formula). Optional but useful additions are safety stock, reorder quantity, supplier, and a date-last-updated cell to force the discipline of keeping it current. Keep it one row per SKU so it sorts and filters cleanly.
T. Brian Jones is co-founder and CTO of Inventory Hero. He leads the engineering behind its Amazon data pipeline, demand forecasting, and the AI platform that lets sellers talk to their live inventory, sales, and supplier data in plain language.
Is a spreadsheet good enough for Amazon inventory?
For a small catalog with steady demand, yes; a disciplined spreadsheet with days-of-supply and reorder-flag formulas covers the basics. It breaks down as SKUs, seasonality, and open purchase orders multiply, because it does not sync with your live sales and stock, so the numbers go stale exactly when accuracy matters. When keeping it current becomes a job in itself, that is the signal to move to software.
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You can manage Amazon inventory in Excel or Google Sheets, and for a small catalog a disciplined spreadsheet does the job. The short version: track on-hand, inbound, velocity, and cost per SKU, add two formulas (days of supply and a reorder flag), and refresh it from your Seller Central reports on a cadence, and its ceiling is that it does not sync, so it goes stale between updates. Below is a practical setup and when to graduate.
A list of stock levels is not management; the formulas are what make the sheet useful:
Days of supply = units on hand / average daily sales. If you hold 400 units and sell 20 a day, that is 20 days of supply. This tells you how long current stock lasts.
Reorder flag = a formula that turns on when days of supply drops below your lead time plus a safety buffer. In a cell, something like: if (days of supply is less than lead time plus buffer) then "REORDER" else "ok".
With those two, the sheet stops being a static list and starts telling you what to do: any row flagged "REORDER" needs an order now. Add a reorder point and safety stock column if you want the trigger in units rather than days.
A starter layout, one row per SKU, covers the essentials:
Column
What it holds
Source
SKU / Name
Identifier
Your catalog
On hand
Sellable FBA units
Manage FBA Inventory
Inbound
Units on the way
Manage FBA Inventory
Daily sales
Trailing velocity
Business Reports
Lead time (days)
Reorder to sellable
Your records
Landed cost
Per-unit cost
Your records
Days of supply
On hand / daily sales
Formula
Reorder flag
Fires below threshold
Formula
Keep the editable inputs on the left and the computed decisions on the right, with a date-last-updated cell at the top. That separation is what keeps the sheet trustworthy as it grows.
A spreadsheet has real advantages and a hard ceiling:
Pros. Free, flexible, and yours; you understand exactly how every number is derived, which is genuinely valuable when you are learning what to track.
Cons. It does not sync, so it is only as current as your last manual update; it does not scale, because refreshing dozens of SKUs by hand becomes a chore; and a stale sheet gives false confidence, which is worse than no sheet.
For a small, steady catalog, the pros win. As complexity grows, the cons compound.
Refreshing it is a recurring chore you dread or skip, so the data is usually stale.
You have many SKUs and open POs, and tracking on-order by hand is error-prone.
Seasonality complicates velocity, so a static trailing average keeps misleading you.
You have been burned by a stale number, a stockout or overbuy the sheet should have caught.
At that point, software that syncs your live sales and stock removes the manual refresh, keeping the same days-of-supply and reorder logic current automatically. The spreadsheet taught you what to track; the software just keeps it honest at scale.
Managing Amazon inventory in Excel comes down to one row per SKU, the right columns (on-hand, inbound, velocity, lead time, cost), and two formulas (days of supply and a reorder flag), refreshed on a cadence from your Seller Central reports. It works well for a small catalog and hits a ceiling when the manual refresh becomes a job and the data goes stale. Learn what to track on the sheet, then graduate when it stops keeping up. For the discipline behind it, see stock management; for the wider system, restock planning.