Most store owners restock when they notice a shelf is empty. By then, you've already missed sales — sometimes days of them.
Quick Answer
A par level is the minimum quantity of a product you want to have on hand at any time — your floor before you're in trouble. A reorder point is the specific count that triggers a new order, factoring in how long it takes your supplier to deliver. If your par level for water is 2 cases and your supplier takes 2 days, your reorder point is whatever you'll sell in those 2 days plus 2 cases.
Why does reactive restocking cost you money?
The IHL Group estimates that stockouts cost retailers $1.75 trillion annually worldwide. For a small store, a single stockout of a fast-moving item — bottled water, eggs, bread — can mean dozens of lost sales per day. And according to the National Retail Federation, 72% of shoppers won't wait for an out-of-stock item. They buy from a competitor.
The problem with reactive restocking is simple: you're always one step behind. You notice a product is gone, you place an order, and you wait. During that wait — which could be 1-3 days for most suppliers — your shelf sits empty and you're turning away customers.
The fix is to reorder before you run out.
What is a par level and why does every product need one?
A par level is the minimum acceptable quantity for a product. It's your floor — the point below which you're uncomfortable.
Set it wrong (too low) and you'll run out. Set it too high and you tie up cash in excess inventory. The right par level depends on:
- How fast the product sells — a case of water might sell in a day; a specialty sauce might last a week
- How critical the product is — missing milk is worse than missing a niche condiment
- How often you can reorder — daily delivery routes give you more flexibility than once-a-week supplier runs
Par levels aren't set once and forgotten. They shift with seasons, promotions, and customer buying patterns. A cold snap raises demand for hot beverages. Summer doubles water sales. Review them quarterly.
How do you calculate a reorder point?
The formula:
Reorder Point = (Average Daily Sales × Lead Time in Days) + Safety Stock
Walk through it:
- You sell an average of 12 units of orange juice per day
- Your supplier delivers in 2 days
- You want 1 day of safety stock (12 units) in case of a delay
Reorder Point = (12 × 2) + 12 = 36 units
When your orange juice count hits 36, place the order. By the time the delivery arrives in 2 days, you'll have used those 24 units — and the safety stock keeps you from running dry if delivery is late.
How does supplier lead time factor in?
Lead time is the gap between placing an order and receiving product. For most small grocery and convenience stores, this ranges from same-day (cash-and-carry) to 3-5 days (broadline distributors).
If your lead time is short and consistent, you can run leaner. If your main supplier is unpredictable — deliveries vary by 1-2 days — build a larger safety buffer. A missed delivery from a 2-day supplier becomes a 4-day wait if they're delayed. Your reorder point should account for that.
For seasonal products or items sourced from a single vendor, build an extra week of buffer around peak periods.
What is the difference between reorder point and par level in practice?
Think of them as two different triggers:
- Par level: "I'm uncomfortable with less than this on the shelf." It's the emergency minimum.
- Reorder point: "I need to order now so I don't hit par level before the delivery arrives." It's the proactive trigger.
Your reorder point will always be higher than your par level when there's any lead time. If they're equal — or if you're ordering only when you hit par — you'll run out during the delivery window.
How does RetailWatcher's Restock Advisor work?
RetailWatcher calculates your average daily sales velocity from your purchase and sales records, then applies your supplier lead times to suggest reorder points for each product. When inventory hits the threshold, you get an alert before the shelf empties.
You set the parameters once:
- Par level for the product
- Supplier lead time
- Safety stock preference
RetailWatcher monitors stock levels continuously and flags products approaching their reorder point. You see the alert, place the order, and the shelf stays full.
The goal is to turn restocking from a reactive scramble into a predictable, proactive routine — where you're always ahead of what your customers need.
Frequently Asked Questions
What is a par level in inventory?
A par level is the minimum stock quantity you want to maintain for a product at any given time — your safety floor. If stock drops below par, you're at risk of running out before your next delivery. RetailWatcher lets you set par levels for every product and alerts you when you're approaching them.
How do I calculate my reorder point?
The formula is: Reorder Point = (Average Daily Sales × Supplier Lead Time in Days) + Safety Stock. For example, if you sell 10 units per day and your supplier takes 3 days to deliver, and you want 1 day of safety stock, your reorder point is (10 × 3) + 10 = 40 units. When your stock hits 40, place the order.
How much safety stock should I keep?
For most grocery and convenience store products, 1-3 days of average sales is a reasonable safety stock. Fast-moving staples (water, bread, milk) warrant more buffer because the cost of a stockout is high. Slow movers can run leaner. RetailWatcher's Restock Advisor calculates suggested safety stock based on your actual sales velocity and supplier lead times.
Can RetailWatcher alert me when stock is low?
Yes. RetailWatcher's Restock Advisor monitors your inventory levels and sends you an alert when a product approaches its reorder point. You set the reorder point and par level once per product, and RetailWatcher handles the monitoring automatically — no daily manual checks required.
What is the difference between reorder point and par level?
Par level is the minimum you always want on hand — your floor. Reorder point is the trigger that tells you to place an order. Your reorder point should be higher than your par level, because it accounts for the time it takes for the new stock to arrive. If your reorder point equals your par level, you'll be out of stock while waiting for delivery.