Inventory Reorder Point & Safety Stock Calculator
Work out when to reorder and roughly how much to buy from current stock, recent sales, supplier lead time, safety stock, reserved quantity, on-order stock and MOQ.
Plan one item
Example is prefilled. Replace it with one of your own SKUs or items.
Why the tool recommends this
Numbers below use the inputs above. Units are rounded up only where a whole-unit operational decision is needed.
How this inventory reorder calculator works
The calculator uses recent sales as a simple demand-rate estimate. It converts your last 30 days of sales into average daily demand, then combines that with supplier lead time and your chosen safety-stock buffer.
1. Available stock and inventory position
Available now = current stock − reserved stock.
Inventory position = current stock + on-order stock − reserved stock. Inventory position is useful for reorder decisions because existing purchase orders can reduce the amount still needing replenishment.
2. Safety stock
Safety stock = average daily demand × safety days. This is a simple days-of-cover method, not a statistical service-level model.
3. Reorder point
Reorder point = lead-time demand + safety stock. Lead-time demand is average daily demand multiplied by supplier lead time. The calculator adds the exact decimal values first and rounds only the final operational reorder point, avoiding misleading sums caused by separately rounded display values.
4. Suggested order quantity
A reorder point tells you when to order; it does not by itself tell you how much to order. That is why this tool also asks for a target stock cover. Target stock cover means the total desired stock cover after replenishment arrives; the safety buffer is already included in that total and is not added a second time.
When reorder is already due, the calculator projects how much sellable stock may remain at the end of the lead-time window. Available stock is not allowed to fall below zero in the purchase calculation. If demand may exceed available stock before replenishment arrives, the tool shows that separately as a shortage risk. The calculator then estimates the quantity needed to reach your chosen target cover after replenishment arrives. When reorder is still in the future, it assumes stock will fall to the safety-stock buffer by the time a correctly timed replenishment arrives. The final quantity is rounded up to the MOQ or case pack you enter.
How to choose safety stock
This calculator deliberately uses a transparent days-of-cover safety stock method: average daily demand × safety days. It works well when you want an explainable planning buffer and do not have clean demand-variability data.
Other safety-stock methods are useful in different situations:
- Fixed-unit buffer: keep a known number of extra units based on operating experience.
- Maximum-demand / maximum-lead-time method: useful when you track realistic high-demand and long-lead-time observations.
- Statistical service-level method: uses demand variability, lead-time variability and a chosen service level. It needs better historical data than this single-SKU V1 asks for.
If your demand is highly seasonal or supplier lead times vary sharply, treat this tool as a planning starting point rather than a forecasting model.
Common reorder-point mistakes
- Ignoring stock already on order. That can make you purchase the same shortfall twice.
- Ignoring reserved or committed stock. Physical stock is not always freely available stock.
- Mixing time units. Daily demand should be paired with lead time expressed in days.
- Using the supplier's transit quote as total lead time. Include order processing, transport, receiving and the time until stock is actually usable.
- Using stale demand. A reorder point based on a quiet month may be too low before a peak season.
- Confusing reorder point with order quantity. Reorder point answers when to order; target cover and MOQ help estimate how much to order.
How often should you review reorder points?
Review the inputs whenever sales velocity, supplier lead time, pack size or seasonality changes materially. Fast-moving or seasonal items may need frequent review, while stable items can be revisited less often. The important point is to avoid treating an old reorder point as permanent.
Important assumptions
This is a planning calculator, not a forecasting engine. It assumes recent demand is a reasonable guide to near-term demand and that an existing on-order quantity will be available within the supplier lead-time window.
It does not yet model seasonality, demand volatility, supplier lead-time variability, multi-location transfers, unmet demand after stock reaches zero or statistical service levels. Those need more data than a simple single-SKU calculator can reliably infer.
Common questions
What is the difference between safety stock and reorder point?
Safety stock is your buffer. Reorder point includes both expected demand during supplier lead time and that safety buffer.
Why does the calculator ask for target stock cover?
Because reorder point alone determines timing, not purchase quantity. Target cover gives the calculator an order-up-to level for estimating how much stock to replenish. It is the total desired cover after the new stock arrives, including the safety buffer.
How should I choose target stock cover?
Target cover is the stock you want available immediately after replenishment arrives. It should normally be comfortably above your safety-stock buffer. A very low target can produce a very small suggested order even when reorder timing is correct.
Does Kavit upload my stock numbers?
No. This public tool calculates in your browser. The values you enter here are not sent to Kavit's API or stored in the Kavit database.
Can I use 90-day or seasonal sales?
This first version deliberately uses a transparent 30-day demand rate. For seasonal, volatile or slow-moving inventory, use a longer planning history and a more advanced demand model rather than treating one recent month as a perfect forecast.