Inventory Forecasting Excel Template (Free) — From a Warehouse Operator Who Outgrew It
I ran a 3PL on spreadsheets for five years before I built forecasting software. Here’s the exact template we used to run an Amazon brand with a warehouse split — plus the honest week it stopped working and what to do about it.
Quick Answer
This free inventory forecasting Excel template tells you how many units to reorder this week for every SKU you sell — across Amazon FBA and your own warehouse or 3PL. It uses a simple, operator-tested approach: daily sales velocity × days of coverage × channel split, minus whatever’s already on order.
Three inputs per SKU, three account-wide settings you set once, and the sheet does the rest. No FORECAST.ETS gymnastics, no Z-scores, no statistical PhD required. It’s the same tool I used to run a real brand before I built software.
Download it below and be running forecasts in about fifteen minutes.
Why I’m writing this post
Most “free inventory forecasting Excel template” pages on the internet are lead-gen bait. They show you a dashboard screenshot, gate a toy spreadsheet behind an email wall, and drop you into a 14-email drip campaign. The templates themselves are usually junk — no channel split, no way to account for open purchase orders, no honest note about where the thing actually helps versus where it leaves you exposed.
I’m not interested in that. I ran a third-party logistics warehouse for five years before I started SKU Compass. I built this spreadsheet because it’s what we could afford, and I used it every Monday morning to decide what to reorder from the manufacturer and what to ship into Amazon FBA. It worked beautifully for the first few hundred SKUs. Then it started to lie to me. I’ll tell you exactly when.
So here’s the honest version: the real template, how it works, what it does and doesn’t do, and the signs that tell you it’s time to stop running inventory from a workbook.
What the template actually does
This is a days-of-coverage replenishment planner. That’s a long phrase for a simple idea: every SKU has a daily sales velocity, and your job is to keep enough stock on hand to cover a specific number of days before your next shipment arrives. The template answers one question for every SKU: “How many units should I order or ship this week?”
It’s not a statistical forecaster. It won’t detect seasonality for you, and it doesn’t calculate safety stock with Z-scores and standard deviations. Most free templates online pretend to do that math, and in practice it’s theater — nobody has the clean historical data to make those formulas reliable, and the answers usually end up worse than a good velocity-based rule.
The operator approach is different and more honest: decide how many days of coverage you want, and let current sales velocity do the rest.
How it works in three steps
One sheet. One row per SKU. Three inputs you fill in, three defaults you set once, and the template writes the reorder list for you.
Enter three numbers per SKU
Units per day — your daily sales velocity, split by channel. One column for Amazon FBA sales, one for Shopify / direct / wholesale sales. Pull these from the last 30–90 days of order history.
Stock on hand — your current inventory, split by location. One column for what’s in FBA, one for what’s in your warehouse or 3PL. This is the split that trips up 90% of Amazon sellers — more on why below.
Purchase orders — units already incoming on open POs. Critical for preventing double orders. If you forget this column, the template will tell you to reorder things you just ordered last week.
Set three account-wide defaults (once)
This is the operator move. Instead of asking you to configure lead time, safety stock, and target stock for every single SKU, the template has three numbers that apply to every row. You set them at the top of the sheet and forget them.
Account defaults (editable)
The three numbers add up to what we call MSF — Manufacture + Safety + FBA. It’s the total days of coverage you want across your whole supply chain: enough stock to survive a late factory, a rough quarter, and the inbound check-in time at Amazon. The defaults above are a sensible starting point for most Amazon sellers buying from overseas. If your lead time is 30 days instead of 90, change one number and the whole sheet updates.
Read the output columns
The template calculates four numbers for every SKU, automatically:
- Days of stock at FBA — how long your current FBA inventory lasts at the current sales pace
- Days of stock at warehouse — same thing for your 3PL or Shopify fulfillment location
- Units to ship to FBA — how many units to transfer from your warehouse into Amazon to hit the 40-day FBA target
- Units to reorder from the manufacturer — the total quantity to buy right now to hit the 175-day MSF coverage, minus anything already on open PO
That’s the entire Monday morning restock meeting in one column. Sort the sheet by “units to reorder” descending, work top to bottom, and you’re done.
Grab the template (free)
The Excel file below is ready to run — the three defaults are pre-set to the values above, and it includes two sample SKUs so you can see the formulas firing before you drop in your own data. Drop your email below and it’s yours.
What most free templates skip (and why it matters)
I read the top ten results for this query before I wrote this post. Almost every one skips three things that matter for real Amazon and multi-channel sellers. Here’s what they’re leaving out and why this template handles each.
The FBA / warehouse split
If you sell on Amazon FBA and also run a warehouse, 3PL, or Shopify fulfillment out of a separate location, you don’t have one inventory bucket — you have two. The one at FBA sells through faster (higher velocity, shorter lead time to replenish: just send a box). The one in your warehouse is the reserve that feeds FBA and also ships direct to Shopify customers.
A template that puts “total inventory” into a single column will consistently tell you to reorder too late, because it doesn’t see that your 60 days of “total” coverage is actually 10 days of FBA and 50 days of warehouse. By the time the 50 days of warehouse stock runs down to zero, you’ve already been out of stock at FBA for a month. The template splits FBA and warehouse into separate columns from the start.
Open purchase orders
Every other free template I looked at asks for current stock but ignores what’s already on the way. If you ordered 5,000 units last week that ship in 60 days, and the template doesn’t know that, it’ll tell you to order another 5,000 this week — and you’ll find out in two months when a container shows up you didn’t plan for. The template has a dedicated “Purchase Order Units” column that subtracts from every reorder calculation. It’s one field. It saves brands from the most expensive mistake in inventory.
Lead time including shipping
Factory lead time is not the same as lead time. A factory that says “30 days production” usually means 30 days after deposit clears, then 3 weeks to the port, then 2–4 weeks on the water, then 1–2 weeks customs and inbound check-in at FBA. The real lead time for most overseas brands is 75–110 days, not 30. The default in this template is 90 — an honest middle-of-the-road number for overseas buying. If you source domestically, change it to 14 or 21 and the whole sheet recalculates.
Setting once, applying to all SKUs
The three defaults — lead, safety, FBA — apply to every SKU on the sheet. Every competitor template either hard-codes these per row (tedious, error-prone) or asks you to calculate per-SKU safety stock with a Z-score formula (impressive-looking, useless in practice). The operator answer is: set the three numbers you’d actually defend in a meeting, apply them to everything, override specific SKUs only when you have a real reason to. Simple beats fancy.
The numbers from running this for five years
I don’t trust inventory content that doesn’t show real numbers, so here are mine from the 3PL era:
A 40-minute recalc is survivable. An 18-thousand-dollar stockout on a SKU that had been a top-5 seller for six months is the kind of thing that makes you rebuild your whole approach. The spreadsheet had correctly predicted the stockout — the problem was we didn’t open the file that Monday because we were busy. That’s the part no template can fix.
When Excel is exactly the right tool
If you have fewer than 100 SKUs, one or two sales channels, and one person who reliably opens the file every week, a good Excel template is the best tool you can use. It’s free, it’s transparent, it forces you to understand your own business, and it surfaces questions that automated software hides.
Most brands under $500K in revenue should not be paying for inventory software. They should be running a real spreadsheet, reviewed every Monday, for about forty-five minutes. That’s the template we’re giving you.
The graduation checklist: 7 signs your spreadsheet is costing you more than software
A spreadsheet stops being free the moment you’re losing more revenue to stockouts and overstocks than a software subscription would cost you. Here’s how to know you’ve crossed that line. If three or more of these are true, the template is now the bottleneck:
Signs it’s time to graduate
If you recognize three or more of those, the spreadsheet has already quietly become the expensive option. Software doesn’t have to mean enterprise bloat — SKU Compass starts at a Tier 1 plan that does the exact same reorder math from this template, but across 100% of your SKUs every night, pulling live velocities from every channel, with no Monday morning recalc to forget.
Frequently asked questions
What’s the best way to forecast inventory in Excel?
For most ecommerce brands under a few hundred SKUs, the best approach is a days-of-coverage replenishment model: daily sales velocity × target days of coverage, split by fulfillment location, minus what’s already on order. It’s simpler and more reliable than statistical forecasting with FORECAST.ETS or Z-scores for safety stock, because those formulas require clean historical data most brands don’t have. The template in this post uses the days-of-coverage approach.
How many days of stock should I keep on hand?
For overseas manufacturing with 60–90 day lead times, target roughly 175 days of total coverage: 90 days of manufacturing lead time, 45 days of safety stock buffer, and 40 days of target stock at FBA. Domestic manufacturers with 14-day lead times can run much leaner — 60–75 days of total coverage is usually enough. Adjust the three defaults in the template to match your actual supplier situation.
How do I account for open purchase orders in a forecasting spreadsheet?
Add a dedicated “Purchase Order Units” column that tracks units already ordered but not yet received. Every reorder calculation should subtract the PO quantity from the raw reorder recommendation. Without this column, you’ll consistently double-order whenever there’s a ship in transit, which is the single most expensive mistake in a homemade spreadsheet. The template in this post has the column built in.
Should I forecast FBA and warehouse inventory separately?
Yes. FBA and warehouse/3PL inventory sell through at different velocities (FBA is usually faster) and replenish on different lead times (topping up FBA from your own warehouse is a same-week ship; reordering from a factory is 60–90 days). Pooling them into one “total inventory” number hides the FBA stockout that’s about to happen. Split them into separate columns and calculate days of stock for each.
At how many SKUs does Excel stop working for inventory forecasting?
In our experience running a 3PL on spreadsheets, the practical ceiling is around 150–250 SKUs on a single channel, or ~100 SKUs across multiple channels. Past that, Monday morning recalcs start taking over an hour, daily velocity numbers get stale because refreshing them is tedious, and version control becomes a real problem. We ran ours to about 400 SKUs before it became the most expensive free tool in the warehouse.
Does this template handle seasonality?
Not automatically. It uses your most recent daily velocity, so if you’re heading into your busy season, you need to update the “units per day” column to reflect the run rate you’re expecting — not the one from 60 days ago. Most brands handle this by refreshing velocities monthly or reviewing the top 20% of SKUs manually before a peak period. Automated seasonal detection is one of the things that pushes brands from a spreadsheet to dedicated software.
How accurate is an Excel template vs dedicated inventory software?
For a well-built spreadsheet like this one, accuracy is within a few percent of dedicated software on stable SKUs. The gap widens on volatile SKUs, new launches, multi-channel brands, and any business where “refresh the daily velocities” stops being a weekly habit. Under 100 SKUs on one channel, the difference rarely justifies paying for software. Over 200 SKUs on two channels, it almost always does.