01
LEAD-TIME DEMAND
280 units20 sold each day × 14 daysInventoryFREE · NO SIGNUP
Reorder Point Calculator
Know when to reorder before stock gets tight. Calculate a per-SKU trigger from daily sales, supplier lead time, and your safety-stock buffer.
FREE TO USEA LOOK ATLAS TOOL
01 USE IT NOW02 NO ACCOUNT03 FIELD NOTES BELOW
INVENTORY TRIGGER
Calculate the stock level that should start your next order.
Use one SKU and one location at a time. Your stock unit can be pieces, cases, or cartons, as long as every field uses the same unit.
LOAD AN EXAMPLE
02
YOUR TRIGGER
Reorder at
340UNITS
Place the next purchase order when your inventory position reaches this level.
DAILY SALES20
×LEAD TIME14 days
+BUFFER60
- Expected sales during lead time
- 280 units
- Safety-stock buffer
- 60 units
- Trigger before rounding
- 340 units
Add current inventory on the left to see whether this SKU has already reached the trigger.
10
ONE SKU, A CLEAR SIGNAL
Order before the rail runs empty.
The same scarlet jacket repeats across the stockroom. Daily demand and supplier lead time define how much inventory the wait consumes; your safety stock protects what remains.
WORKING VIEW
PLACE THE ORDER AT340 UNITS
280 UNITSCOVER 14 DAYS OF SALES
60 UNITSREMAIN AS THE BUFFER
- 01ORDER PLACED
- 02LEAD-TIME DEMAND
- 03DELIVERY ARRIVES
THE FIELD NOTES
Quick answer above. Better decisions below.
Use the result now, then read the practical notes for assumptions, examples, limitations, and the choices behind it.
THE REORDER POINT FORMULA
Demand during the wait, plus the buffer you choose.
02
SAFETY STOCK
60 unitsYour buffer for delay or extra demand03
REORDER POINT
340 unitsPlace the purchase order hereWHAT THE 340 UNITS DOOrder here. The remaining stock covers the wait.
280 UNITSCOVER 14 DAYS OF EXPECTED SALES
60 UNITSREMAIN AS THE BUFFER
- DAY 0Purchase order placed at 340 units
- LEAD TIMEExpected demand uses 280 units
- DAY 14Delivery arrives with 60 buffer units left
BETTER INPUTS, BETTER SIGNAL
How to calculate your reorder point.
- 01
Find average daily sales
Divide units sold by days in the period. Exclude a stockout period if it hid demand, and use a forward-looking rate for a launch or promotion.
- 02
Count the full lead time
Measure from purchase-order placement until stock is actually available to sell, including production, freight, customs, receiving, and putaway.
- 03
Choose a real safety buffer
Use the extra units your operation is willing to hold for supplier delay or demand variation. There is no one universal safety-stock formula.
- 04
Recalculate as conditions move
Update the trigger when sales velocity, supplier performance, channel mix, or seasonality changes. A static reorder point eventually becomes stale.
PLANNING LIMIT
A clean formula cannot rescue misleading inputs.
Historical sales may understate demand after a stockout. Promotions and seasonality can make an old average too low. Confirmed incoming stock can make the urgency check look safer even when that shipment arrives later than expected.THREE NUMBERS. THREE JOBS.
Reorder point is when, not how much.
Safety stock
Extra units held against demand spikes or supply delays.
Protects the waitReorder point
The inventory position that should trigger the next purchase order.
Starts the orderOrder quantity
The number of units to buy after the trigger is reached. This tool does not calculate it.
Sizes the orderINVENTORY PLANNED. PRODUCT NEXT.
Now make the product worth waiting for.
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How to calculate average daily demand
Choose a recent period that reflects how the SKU is selling now, then divide the units sold by the number of calendar days in that period. If 420 units sold over 30 days, average daily demand is 14 units. The period needs enough normal selling days to smooth random noise without hiding a real change in demand.
Historical sales are not always the same as demand. A stockout can suppress the units customers were able to buy, while a launch, promotion, or marketplace feature can lift the rate temporarily. For seasonal products, use a comparable upcoming period or a forecast that reflects the event instead of relying on a quiet annual average.
What counts as supplier lead time?
Lead time starts when you place the order and ends when the units are available to sell. Include supplier processing or production, freight, customs, warehouse receiving, quality checks, labeling, and putaway. A factory quote of seven production days is not a seven-day lead time when the stock still spends two weeks in transit.
Use a representative total rather than the fastest shipment you have ever received. If lead time varies materially, pair a conservative lead-time assumption with a safety-stock policy your business can afford, and review the trigger when supplier performance changes.
Reorder point with and without safety stock
Without safety stock, the trigger is simply expected demand during lead time. Five units per day with a 10-day lead time gives a 50-unit reorder point. Adding 20 units of safety stock moves the trigger to 70 units, so the purchase order starts earlier and preserves that buffer through the expected wait.
Safety stock is a business choice, not a magic number. It depends on demand variability, supplier reliability, service goals, expiry, storage, and cash. This free reorder point calculator asks you to supply the buffer instead of silently applying a universal formula that may not fit your operation.
INVENTORY FIELD NOTES
Five mistakes that move the trigger in the wrong direction.
Use one SKU-location
Demand and available inventory need the same scope. Do not mix a regional warehouse with sales from stock it cannot fulfill.
Measure actual door-to-shelf time
A supplier's production quote is not the full lead time when freight, customs, receiving, or putaway delay availability.
Review after stockouts
Observed sales can fall because the product was unavailable. Replace that distorted average with a better demand estimate.
Plan promotions separately
A campaign, marketplace feature, or seasonal peak can make the normal daily rate too low for the next replenishment cycle.
Keep order size separate
The trigger tells you when to buy. Case packs, minimums, cash, storage, and EOQ determine how much to buy.
Reorder point examples for ecommerce sellers
A Shopify brand, an Amazon FBA seller, and an Etsy shop can use the same core formula because the trigger is based on inventory flow, not marketplace fees. What changes is the scope. A shared warehouse can use combined channel demand when every order draws from the same stock. Separate FBA, retail, and regional warehouse pools should normally have separate SKU-location calculations.
Compare the result with inventory position, not blindly with the number sitting on one shelf. Inventory position adds confirmed incoming stock and subtracts committed or backordered units. Check timing as well: a purchase order arriving after the current stock runs out should not be treated as if it were available today.
What this inventory reorder point calculator does not model
The result is a planning threshold from the values entered. It does not automatically account for seasonality, promotions, supplier disruption, minimum order quantities, case packs, expiry, storage limits, cash constraints, returns, or sales history distorted by a stockout. It also does not calculate economic order quantity or recommend how many units to buy.
Recalculate each SKU-location when demand or lead time changes. For expensive, perishable, highly seasonal, or service-critical inventory, use this transparent result as one input to a fuller replenishment policy rather than a guarantee against stockouts.
Questions, answered.
What is a reorder point?
A reorder point is the inventory position that should trigger your next purchase order. It is designed to cover expected demand during supplier lead time plus any safety-stock buffer you choose.
What is the reorder point formula?
Reorder point = average daily demand × supplier lead time + safety stock. This calculator keeps full precision through the calculation and rounds the final trigger up to the next whole unit.
Does a reorder point include safety stock?
It can. Safety stock is an optional buffer added to expected lead-time demand. Leave it at zero for a basic trigger, or enter a buffer based on your own demand and supplier risk.
How do I calculate average daily sales?
Divide units sold by the number of calendar days in a representative period. Review whether stockouts, promotions, launches, or seasonality made that historical rate unusually high or low.
What should supplier lead time include?
Count the full time from placing the purchase order until the units are available to sell. That can include production, freight, customs, receiving, inspection, and warehouse putaway.
Is reorder point the same as safety stock or order quantity?
No. Safety stock is the buffer. Reorder point tells you when to order. Order quantity or EOQ tells you how much to buy, which this calculator does not estimate.
Should I compare the trigger with on-hand stock?
Inventory position is usually more useful: on-hand units plus confirmed incoming units minus committed or backordered units. Keep the timing of incoming stock in mind because a late receipt can make the check look safer than it is.
Can I use this for Shopify, Amazon FBA, Etsy, or multiple marketplaces?
Yes. The formula is platform-agnostic. Calculate one SKU-location at a time, or combine demand and inventory only when the same stock pool genuinely serves every included channel.
Can a reorder point guarantee I will not stock out?
No. It is a planning estimate based on the values entered. Demand spikes, supplier disruption, late receipts, minimum order quantities, cash constraints, expiry, and stockout-censored sales history can change the real outcome.
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