Expiration Date Calculator

How the calculation works

Expiration date = manufacturing date + stated duration. Adding calendar months keeps the day number, or uses the last day when that day does not exist.

Inputs

• Manufacturing date
• Duration
• Duration unit

Calculation details

January 31, 2026 plus one calendar month gives February 28, 2026. This differs from adding a fixed 30 days.

The date marks the end of the full interval; the previous calendar day is shown separately. Labeling determines whether boundary dates are included. This does not assess product condition or storage effects.