# Medical Inventory Reorder Calculator

> Find the reorder point, par level and order quantity for medical supplies or medicines from daily usage, supplier lead time, order cycle and safety stock.

Category: Healthcare operations · Applies to: Worldwide · Last updated: 2026-10-29
Interactive calculator: https://calculators.geekmidst.com/calculators/medical-inventory-reorder-calculator

Reorder when stock on hand plus stock on order falls to the usage expected during the supplier’s lead time plus your safety stock. Then order back up to the par level.

Also called: Par level calculator, Medical supplies reorder point calculator.

## Inputs
- Average daily usage (unit units/day; default 40)
- Supplier lead time (unit days; default 5)
- Days between orders (unit days; default 7)
- Safety stock (unit units; default 60)
- Stock on hand (unit units; default 180)
- Already on order (unit units; default 100; optional)

## Results
- Quantity to order now
- Reorder point
- Par level (order-up-to)
- Days of stock on hand
- Status

## Formula

```
Reorder point = Daily usage × Lead time + Safety stock;  Par level = Daily usage × (Lead time + Days between orders) + Safety stock;  Order = ⌈Par level − On hand − On order⌉ (not below 0)
```

Where:
- Daily usage: average units used per day
- Lead time: days from placing an order to receiving it
- Safety stock: buffer kept for demand spikes and late deliveries

## Worked example
1. Reorder point = 40 × 5 + 60 = 260 units.
2. Par level = 40 × (5 + 7) + 60 = 540 units.
3. Order = 540 − 180 − 100 = 260 units.

**Result:** Using 40 units a day with a 5-day lead time and a weekly order, order 260 units now to bring stock back to the 540-unit par level.

## What the result means

Order the suggested quantity at each review. If you keep running out, raise the safety stock or shorten the order cycle; if stock expires on the shelf, lower the par level for that item.

## Assumptions and limits
- Usage and lead time are steady at the averages entered.
- Safety stock is set by you; no statistical service level is assumed.
- Pack sizes, minimum order quantities and expiry dates are not considered; round to whole packs yourself.

## Questions

### How much safety stock should a clinic keep?

Enough to cover the worst realistic mix of higher usage and late delivery. Critical items usually get a larger buffer than routine consumables.

### What is a par level?

The stock you top up to at each order. It covers usage until the next delivery after the next order, plus safety stock.

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- [Medication Days Supply Calculator](https://calculators.geekmidst.com/calculators/medication-days-supply-calculator)
- [Average Calculator](https://calculators.geekmidst.com/calculators/average-calculator)

Source: GM¹X CalcVerse — https://calculators.geekmidst.com/calculators/medical-inventory-reorder-calculator