How do you forecast demand from Xero sales history?

To forecast demand from Xero, export the Inventory Item Details report for the last one to three years, total each item's units sold by month in Excel, and average recent months to get a demand rate. Multiply that rate by lead time plus safety stock for a minimum, and add a review period's demand for a maximum.

Does Xero forecast inventory demand?

Not in core Xero. Its inventory reports show history: the Inventory Item List shows stock on hand and Inventory Item Details shows past sales and purchases. There is no reorder point field and no projection of future demand, so any forecast is one you build.

The history you need is there. Inventory Item Details lists sales and purchase lines by item and date, which is all a basic forecast needs.

How do you get the sales history into Excel?

1. Go to Accounting, then Reports, and open Inventory Item Details.
2. Set the date range from 12 to 36 months ago up to today, and leave every item selected. Three years lets you see whether a peak repeats.
3. Click Update, then Export, and choose Excel.
4. Also export the Inventory Item List as at today for quantity on hand.
5. Note what is already on order from the Approved tab under Purchases, then Purchase orders.

Keep only sales lines when you total demand; purchase lines are stock coming in, not demand. Our Xero inventory reports guide explains what each report covers.

How do you calculate min and max in Excel?

Build one row per item with a demand rate, then apply four formulas. Use days throughout so lead time and safety stock share a unit.

1. Add a Month column to the sales lines, then build a pivot table with item codes as rows, months as columns and quantity as values.
2. Daily demand = units sold in the last 12 months ÷ 365.
3. Min (reorder point) = daily demand × (supplier lead time days + safety stock days).
4. Max = min + daily demand × days between reviews.
5. Order quantity = max − quantity on hand − quantity on order, rounded up to the supplier's pack size. Order only when on hand plus on order is at or below min.

Example with made-up data: Brightline Supply sold 1,095 units of an Ironwell Tools drill bit set in the last year, so daily demand is 3. Lead time is 10 days, safety stock 5 days, and the buyer reviews every 7 days. Min is 3 × 15 = 45, max is 45 + 21 = 66. With 40 on hand and none on order, order 26, rounded up to a case of 10 makes 30.

Xero has no supplier or lead time on an item, so keep those columns in your sheet. Core Xero also has nowhere to store the min, so the sheet is your low stock list; see the Xero reorder points guide.

What are the common mistakes with a spreadsheet forecast?

• Seasonality. A yearly average under-orders before a peak and over-orders after it. For seasonal items, use the same months last year.
• Lumpy items. One big order can look like steady demand. Count the months with any sales; if there are only a few, plan around a typical order instead.
• Stockouts. Months with no stock show no sales and drag the average down. Leave them out.
• Bills not yet entered. Tracked stock in Xero rises when the supplier's bill is approved, so quantity on hand can look low just after a delivery.
• Stale numbers. Refresh the sheet monthly or quarterly.

How do you spot overstock from the same data?

Compare stock on hand with demand. Weeks of cover is the simplest measure: quantity on hand ÷ weekly demand. Any item well above its max, or with stock and no sales in the past year, is overstock. The Inventory Item List shows the value on hand, so you can see how much cash each one ties up.

Where does ReorderOwl fit?

ReorderOwl replaces the spreadsheet. Upload the Inventory Item List and Inventory Item Details exports and it forecasts each tracked item from its sales history, compares that with quantity on hand, and lists what to order and how much, in a workbook that shows how each number was worked out. It works in ChatGPT today; Claude setup is coming shortly.

When you ask, it builds the purchase order. It does not connect to Xero or change anything there, and nothing is sent to your supplier. See ReorderOwl for Xero.

Frequently asked questions

Can Xero forecast inventory demand?

Core Xero reports show history, not projections. Export Inventory Item Details and forecast in Excel or another tool.

Which Xero report has sales by item and date?

Inventory Item Details shows line-by-line sales and purchase details for each item.

What is the min max inventory formula?

Min equals daily demand times lead time plus safety stock days. Max equals min plus daily demand times the days between reviews.

How much sales history should I use?

Use 12 months for the rate and up to 36 months to check whether seasonal peaks repeat.

Sources

1. Inventory Item Details report, Xero Central, accessed 2026-10-01
2. Inventory Item List report, Xero Central, accessed 2026-10-01
3. Export and print a report, Xero Central, accessed 2026-10-01
4. Strengthen your inventory and purchasing with Xero, Xero, accessed 2026-10-01