How Stash calculates when to reorder
The Order Planner's reorder suggestions aren't magic — they're based on a simple formula combining your consumption rate, lead time, safety buffer, and supplier delivery days. This article explains the math so you can understand (and trust) the recommendations.
The formula
For each item with a primary supplier, Stash calculates:
Consumption rate = average daily usage from recent sales, transfers, and adjustments
Days of stock left = current quantity ÷ consumption rate
Reorder by = today + days of stock left − lead time − safety buffer
Suggested quantity = the reorder quantity set on the item (usually enough for ~2–4 weeks)
If Reorder by is in the past or in the next few days, the item shows up in today's suggestions.
Each input, explained
Consumption rate
Stash looks at how much of an item has been consumed over the recent past — typically the last 28 days. It averages this to a per-day usage. A coffee shop selling 2 kg of beans per week has a consumption rate of ~285 g/day.
The window is rolling — yesterday's data carries more weight than data from a month ago.
Lead time
Set on the supplier (in days). It's how long it takes from placing the order to the stock physically arriving. If your roaster takes 5 days to deliver, set lead time to 5. See Editing supplier details, lead time, and delivery days.
Safety buffer
Set on the supplier (in days). It's a cushion in case the supplier is late. Default is 1 day. If a supplier is famously unreliable, increase it to 3 or 5.
Delivery days
Some suppliers only deliver on certain days (e.g., Tuesdays and Fridays). Stash factors this in when picking the suggested order date — it'll round forward to the nearest valid delivery day.
Reorder quantity
Set on the inventory item. It's how much to order each time. Set this to a value that lasts about as long as the time between expected reorders. For a fast-moving item, that might be 2 weeks of stock; for a slow-moving one, a month or more. See Setting low stock thresholds and reorder quantity.
A worked example
Imagine a coffee shop:
Item: Espresso beans
Current stock: 5 kg
Consumption rate: 0.5 kg/day (averaged from the last 28 days)
Supplier lead time: 4 days
Safety buffer: 1 day
Delivery days: Mondays and Thursdays
Reorder quantity: 12 kg (~24 days of stock)
Math:
Days of stock left = 5 ÷ 0.5 = 10 days
Reorder by = today + 10 − 4 − 1 = 5 days from now
Round to next supplier delivery day → say, this Thursday
So the Order Planner suggests: Order 12 kg of espresso beans by Thursday from your supplier. If you don't, you'll likely run out around 10 days from now (since the supplier needs 4 days to ship and 1 day cushion).
What gets subtracted from "current stock"
Stash counts pending POs as already-arriving stock. So if you have 5 kg on hand but already have a PO for 10 kg in Ordered status, your effective stock for the calculation is 15 kg. This avoids double-ordering. See Understanding PO statuses.
What if my consumption rate is zero?
If an item has had no recent activity (no sales, transfers, or adjustments), Stash can't forecast it. It won't appear in suggestions until you have some consumption history. For brand-new items, just set a manual reorder reminder or trust the low-stock threshold to catch it.
Improving the suggestions
If the Order Planner's suggestions feel off:
Check the supplier's lead time is realistic
Check the safety buffer matches the supplier's reliability
Tune the item's reorder quantity if you're getting orders too frequently or too infrequently
Make sure delivery days are correct on the supplier
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