Reorder Point Calculator
When to place your next purchase order.
Enter your values
Enter the average daily demand in units.
Enter the supplier lead time in days.
Enter the safety stock in units.
Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.
- Reorder point
- 500 units
- Demand during lead time
- 400 units
- Safety stock buffer
- 100 units
- Days of cover at reorder
- 12.5
Quick answer
Reorder point equals average daily demand times lead time in days, plus safety stock.
ROP = (daily demand x lead time) + safety stock
At a glance
| What it does | When to place your next purchase order. |
|---|---|
| Category | Business |
| Inputs needed | Average daily demand, Supplier lead time, Safety stock |
| Main output | Reorder point |
| Formula | ROP = (daily demand x lead time) + safety stock |
| Cost | Free — no sign-up, no download |
How to use the Reorder Point Calculator
- 1Enter average daily demand for the item.
- 2Enter supplier lead time in days.
- 3Add safety stock to cover demand spikes or shipping delays.
Inputs explained
- Average daily demand(units)
- Enter the average daily demand in units.
- Supplier lead time(days)
- Enter the supplier lead time in days.
- Safety stock(units)
- Enter the safety stock in units.
Worked example
Using the values the calculator loads with:
Inputs
- Average daily demand40 units
- Supplier lead time10 days
- Safety stock100 units
Results
- Reorder point500 units
- Demand during lead time400 units
- Safety stock buffer100 units
- Days of cover at reorder12.5
Frequently asked questions
What if lead time varies?
Use the longest realistic lead time, or increase safety stock to compensate.
How does this differ from safety stock alone?
Reorder point includes expected demand during lead time on top of the safety buffer.
What do I need to enter into the Reorder Point Calculator?
Just 3 values: average daily demand, supplier lead time, safety stock. Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.
How does the Reorder Point Calculator work out the answer?
Reorder point equals average daily demand times lead time in days, plus safety stock. It applies the formula ROP = (daily demand x lead time) + safety stock and shows the working so you can check each step by hand.
Is the Reorder Point Calculator free, and do I need an account?
It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.