Pharmacy Stock Expiry Calculator

How to use this calculator

1. Enter or choose units on hand (this batch).
2. Enter or choose average daily usage.
3. Enter or choose days until expiry.
4. Enter or choose cost per unit.
5. The units likely to expire updates as you type. Use Copy result or Share to keep it.

Method

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

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.

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.