# Pharmacy Stock Expiry Calculator

> Estimate how much of a medicine’s stock will expire before it is used, its value, and the daily usage needed to clear it before the expiry date.

Category: Healthcare operations · Applies to: Worldwide · Last updated: 2026-10-29
Interactive calculator: https://calculators.geekmidst.com/calculators/pharmacy-stock-expiry-calculator

Stock at risk is whatever you hold beyond what you will use before the expiry date: units on hand minus daily usage × days left.

Also called: Short-dated stock calculator.

## Inputs
- Units on hand (this batch) (unit units; default 500)
- Average daily usage (unit units/day; default 12)
- Days until expiry (unit days; default 30)
- Cost per unit (default 2.40)
- Currency

## Results
- Units likely to expire
- Value at risk
- Units used before expiry
- Share of stock at risk
- Daily usage needed to clear the batch
- Days to use up at current usage

## Formula

```
Used before expiry = min(On hand, Daily usage × Days to expiry);  At risk = On hand − Used before expiry;  Value at risk = At risk × Unit cost
```

Where:
- On hand: units in the batch that expires
- Daily usage: average units dispensed per day
- Days to expiry: days left before the expiry date

## Worked example
1. Usable before expiry = 12 × 30 = 360 units.
2. At risk = 500 − 360 = 140 units (28% of the batch).
3. Value at risk = 140 × 2.40 = 336.

**Result:** At 12 units a day, 140 of the 500 units (worth 336) are likely to expire unless usage rises to about 16.7 a day.

## What the result means

Act on at-risk stock early: transfer it to a site that uses more, return it if the supplier allows, or make sure it is dispensed first (first-expiry, first-out). Then lower the par level for that item.

## Assumptions and limits
- This batch is used first (first-expiry, first-out).
- Usage stays at the average entered until the expiry date.
- Other batches of the same product that would be used first are not considered.
- Supplier return or credit policies are not included.

## Questions

### How do I count days until expiry?

Count from today to the expiry date on the pack. If the label shows only a month, many products expire at the end of that month; check the product rules.

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Source: GM¹X CalcVerse — https://calculators.geekmidst.com/calculators/pharmacy-stock-expiry-calculator