Safety Stock & Reorder Point Calculator
Set a safety stock that allows for both usage swings and late deliveries. Enter your averages or paste daily usage, choose a service level, and get the reorder point, par level and the value of stock it ties up.
- Demand + lead-time variability
- Paste usage history
- SKU list → CSV
- No sign-up
01Item
02Daily usage
Standard deviation of daily usage
03Supply
Order placed → delivered
How much it varies
Your ordering cycle (review period)
04Service & cost
Chance a delivery cycle doesn’t run out
Reorder point
191cases
Reorder when stock falls to this
Safety stock
65cases
Buffer for a 95% service level
Par level
322cases
Order up to this every 7 days
- Order today
- 162 cases
- Safety stock value
- $4,200
- Avg. stock held
- $8,618
- Expected stockouts
- 2.6 / yr
05Demand over the next 14 days
From ordering until the delivery after next you expect to use 252 cases (σ 42.4). A par level of 322 covers that 95% of the time. The shaded tail is the chance of running out. Your current 160 cases on hand and on order cover it 2% of the time.
06What each extra point of service costs
Safety stock rises steeply as you approach 100%. At 95% you hold $4,200 of buffer; going to 97% would take $4,852.
07Safety stock for a whole SKU list
Paste or edit rows: sku, avg daily usage, usage σ, lead time, lead time σ, unit cost, on hand. Uses the 95% service level and 7-day cycle above.
| SKU | Safety stock | Reorder point | Par level | On hand | Order now | Buffer value |
|---|---|---|---|---|---|---|
| Chicken breast 40lb | 4 | 10 | 34 | 5 | 29 | $609 |
| Romaine hearts 24ct | 2 | 4 | 21 | 3 | 18 | $162 |
| Fryer oil 35lb | 3 | 7 | 18 | 4 | 14 | $151 |
| Burger buns 8ct x 12 | 5 | 11 | 63 | 9 | 54 | $220 |
| To-go clamshell 9in | 5 | 10 | 18 | 6 | 12 | $290 |
| 5 SKUs | $1,432 | |||||
5 SKUs · 1 site · one point in time
These par levels are only right until usage or lead times change. In most kitchens and supply rooms that is next week.
Bollard recalculates par levels for every SKU at every site from actual usage and supplier lead times, then drafts the replenishment order for approval.
Method
The formulas behind the numbers
Safety stock = z × √(L·σd² + d²·σL²). The first term covers usage swings during the lead time; the second covers deliveries that arrive late. Ignoring the second term is the most common reason safety stock fails.
Reorder point = d × L + safety stock, for when you reorder as soon as stock hits a level. Par level = d × (L + R) + z × √((L+R)·σd² + d²·σL²), for when you order on a cycle of R days.
z comes from the inverse normal distribution for your service level (1.645 for 95%, 2.326 for 99%). If you paste usage history, d and σd are calculated from it.
From one site to every site
A safety stock calculated once becomes wrong as soon as usage or lead times change.
Bollard recalculates safety stock and par levels for every SKU at every site from actual consumption and the lead times your suppliers actually deliver, then drafts the replenishment order.
- Par levels that update from real usage
- Supplier lead times measured from receipts
- Replenishment orders drafted per site
- Stockouts and overstock tracked by site
Questions
Frequently asked
What is the safety stock formula?+
This calculator uses safety stock = z × √(L × σd² + d² × σL²), where d is average daily usage, σd its standard deviation, L the average lead time in days, σL the lead-time standard deviation and z the service-level factor. It covers both variable demand and variable lead time.
How do I calculate the reorder point?+
Reorder point = average daily usage × lead time + safety stock. When stock on hand plus stock on order falls to that level, place the next order.
What service level should I use?+
It depends on what a stockout costs. Critical items, such as surgical supplies or a menu’s signature ingredient, often justify 98 to 99.5 percent. Low-impact items can sit at 90 to 95 percent. The cost chart shows how quickly safety stock grows as you approach 100 percent.
What is the difference between a reorder point and a par level?+
A reorder point is used when you watch stock continuously and order when it drops to a set level. A par level is used when you order on a fixed schedule: you top up to par every few days, so it must also cover usage until the next delivery.
What does the service level actually mean?+
It is the cycle service level: the probability that you do not run out during one replenishment cycle. At 95 percent with weekly orders, you would expect to run short in about 2.6 of 52 cycles a year.
Is my data uploaded?+
No. All calculations, including the SKU list and CSV export, run in your browser.
Related tools
All tools- Par Level CalculatorSet par levels for a delivery schedule and see exactly how much to order today, for one item or a whole par sheet.
- EOQ Calculator with Price BreaksEconomic order quantity with vendor price breaks, case-pack rounding and shelf-life limits.
- ABC-XYZ Analysis ToolSort a SKU list into Pareto classes and get a recommended stock policy for each group.
- Expiry Risk & Inter-Site Transfer PlannerFind stock that will expire before it is used and suggest transfers to sites that need it.
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